Hospital bed

ABSTRACT

A patient bed includes a base, a patient support, and an elevation mechanism for raising or lowering the patient support relative to the base. The elevation mechanism comprises a first pair of arms and a second pair of arms, with both the pairs of arms mounted relative to the patient support and the base. The first pair of arms and the second pair of arms have pivot connections at the patient support, with the pivot connections of at least one pair of the pair of arms moving in a sinusoidal path when the patient support is raised or lowered with respect to the base.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from U.S. provisional application Ser.No. 60/______, filed Dec. 11, 2006, entitled HOSPITAL BED, by ApplicantGuy Lemire, and U.S. provisional application Ser. No. 60/751,770, filedDec. 19, 2005, entitled HOSPITAL BED, by Applicant Guy Lemire, which areincorporated by reference herein in their entireties.

FIELD OF THE INVENTION

The present invention relates in general to the field of patient supportapparatuses such as hospital beds. In particular, the invention relatesto critical care patient support apparatuses with improved safetyfeatures, expanded configurability and accessible control andelectronics for users.

BACKGROUND OF THE INVENTION

Hospital beds comprise complex mechanical and electronic components formovement, functionality and convenience.

Foot brakes of prior art hospital beds are typically located on the sideunder the bed. There are certain disadvantages associated with such footbrakes. For example, during activation, a user such as a nurse has tohold on to the bed, balance on one foot and stretch the other foot underthe bed to engage or disengage the brake. As such, if the side rail isin the lower position, visibility is reduced. In addition, if thepatient is exiting the bed, the bed may move which is unsafe.Furthermore, the weight of present day beds and patients are relativelylarge, requiring sufficient braking force to hold a bed in a desiredlocation in a hospital.

There is a need for a braking system which is convenient and safe touse. Such a system can be powered in any manner. There is a further needfor a braking mechanism that can be manually overridden such as if thereis a power failure.

Generally, a bed is moved by a series of internal motors and controlledby means of an interface that can be used by users such as hospitalpersonnel or the patient to adjust the bed to suit the comfort and needsof the patient. For safety reasons, the movement of the bed is quiteslow and there is a need for an override control, to quickly andefficiently bring the bed into a relatively flat position in case ofemergency or for routine tasks such as cleaning, patient transfer orsurgery. In past designs, this override function has been initiatedthrough hand controls, foot controls, or a combination of hand and footcontrols.

In an emergency situation, it is desirable to reposition a bed quicklyand easily into a CPR or Trendelenburg position, to facilitateadministration of CPR or other resuscitation efforts. The manual- ormotor-driven mechanism utilized to raise and lower the Fowler sectiontypically moves too slowly to be acceptable in an emergency situation.Accordingly, emergency releases have been developed to quickly disengagethe Fowler section from the drive mechanism to allow for rapid movement,however, these arrangements can be complex, bulky, expensive anddifficult to engage and disengage.

Movement of the foot-end of a hospital bed to various positions that arenot aligned with the remainder of the bed, such as a chair position, isdifficult when it forms part of the main bed frame

For a patient support apparatus in which movement of the Fowler sectionis effected by a motor-driven mechanism, it would be advantageous to beable to increase the speed at which the Fowler section could be loweredfor CPR and Trendelenburg, beyond that speed which is currentlyobtainable with the motor-driven mechanism powered by a conventionalelectrical power source.

Early designs of adjustable beds often employed the concept of a handcrank and gearing to adjust the height of a bed. Such manual systemssuffer from the need for considerable physical effort to adjust the bedheight. Other designs include elevation systems incorporating mechanicaljacks using hydraulic piston cylinders or screw drives to adjust theheight of the hospital bed. Such hydraulic systems are known to berelatively expensive and prone to leakage. Additionally, priormechanical systems suffer from excessive complexity, excessive size, alack of load capacity, and manufacturing difficulties.

Hospital bed side rails of the prior art comprise support arms whichform undesirable pinch points for users. The movement of such side railsfrom the deployed to the stowed positions is often hampered by side railoscillations. The side rail falls due to gravity and the movement canjar the bed and disturb patients.

In addition, the patient support apparatus of the prior art relies onbatteries to provide all power to the bed's electronic systems. When thebattery power runs out, the battery itself must be recharged beforepower can be supplied to the electronics. This is problematic incircumstances where the life of the battery itself has run out or insettings where a suitable power supply to recharge the battery is notavailable.

In existing apparatuses, the control interface is located on the side orfoot-end of a bed. Often, the operator directs movement of the bed fromthe head-end by pushing on the head-end or push handles located at thehead-end. In the event the position of the patient needs to be adjustedwhile a prior art hospital bed is in motion, the operator has to stopthe bed and move around the bed in order to access the bed controlinterface. If the bed is in a confined space, such as a narrow corridoror elevator, this action may be difficult to execute and result in anundesirable delay in effecting the change in position of the patient.

Currently, the angular position of the patient can be determined bymeasuring the patient's current position with respect to a plane ofreference (e.g., the floor or the bed frame). This technique, however,suffers from the drawback that any misalignment in the frame ofreference severely affects the integrity of the sensed angular position.Another method for inclinometry is by way of gravitationalaccelerometers. When the accelerometer is in a stationary position, theonly force acting on it is the vertical gravitational force having aconstant acceleration. Accordingly, the angular position of the patientcan be calculated by measuring the deviation in the inclination anglebetween the inclination axis and the vertical gravitational force.Although the accelerometers can provide an effective way to measure theinclination in the patient's position, the resolution of thegravitational accelerometers is restricted to a limited range ofinclination angles.

Currently, nurses and other hospital staff hang pumps (or other hospitalequipment) on the top edge of the footboards of hospital beds. Sincefootboards were not designed to support the hanging of pumps (or otherhospital equipment), this current practice reduces access to thecontrols on footboards, damages foot controls and footboards, generatesbed motions and causes damage to pumps (and other equipment) that fallfrom its hangers.

Ordinarily, there is a tendency for detached headboards or footboardsplaced in an upright position against an object or structure to slip,thereby causing the headboard or footboard to fall and potentiallysuffer damage. This is a particularly acute concern in the situation ofa medical emergency during which headboards and footboards may need tobe removed and set aside in haste. In a busy hospital, a discardedheadboard or footboard that has fallen to the floor creates a trippinghazard to both staff, who may be carrying equipment or medication andthus have an obstructed view of the floor, and patients, who may havecompromised mobility owing to illness. Preventing slippage, therefore,reduces the likelihood of personal injury stemming from hastily removedheadboards and footboards.

Existing motorized hospital beds utilize a single speed or multipledefined and preprogrammed speeds for bed movement resulting in the userhaving to manually switch speeds. Variable speeds in these beds are notautomatic

Therefore, there is a need to provide a patient support apparatus suchas a hospital bed which overcomes the problems of the prior art.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a hospital bed. In oneform of the invention, a patient bed includes a patient support, a base,and an electrical control system. The patient support is mountedrelative to the base, which has a plurality of bearing members formoving the base and the patient support across a surface. Each of thebearing members includes a brake operatively associated therewith. Theelectrical control system includes a user actuatable device and isconfigured to actuate one or more of the brakes upon actuation of theuser actuatable device.

In one aspect, the user actuatable device comprises a button or a touchscreen.

In another aspect, the patient support comprises a support frame systemwith the user actuatable device located on the support frame system.

In further aspect, the electrical control system includes an actuatorfor actuating at least one of the brakes. Additionally, a manualoverride mechanism may be provided for decoupling the actuator from thebrake. For example, the manual override mechanism may include a manualoverride pedal or handle.

In other aspects, the control system includes a plurality of actuators,which are operatively associated with the brakes for selectivelyactuating the brakes. For example, the bearing members include forwardbearing members and rearward bearing members, with one of the actuatorsbeing operatively associated with the forward bearing members andanother of the actuators being operatively associated with the rearwardbearing members.

In another form of the invention, a patient bed includes a patientsupport and a base, with the patient support movably mounted relative tothe base. The bed further comprises a headboard, a footboard, and aplurality of side rails. One or more surfaces of the side rails or theheadboard or the footboard includes a gap and a sealing cover forsealing the gap to facilitate cleaning and disinfection of the patientbed.

In one aspect, the sealing cover comprises a removable cover, such as aremovable membrane. In another aspect, the removable membrane includesan adhesive surface for applying and releasably securing the removablemembrane to the surface.

In yet another aspect, the surface includes a recessed portion, with therecessed portion including the gap, and with the cover located in therecessed portion. For example, the cover may be flush with the surfacesurrounding the recess when the cover is mounted in the recess over thegap.

In other aspects, the surface includes an opening, with the patient bedfurther comprising an electronic user interface located in the openingand the cover sealing a gap between the user interface and the surface.

According to yet another aspect, the side rail includes the surface. Forexample, the surface of the side rail may include a plurality ofopenings and a control interface associated with each of the openings.The cover or covers seal the gaps between the control interfaces and thesurface. Further, each of the control interfaces may include one or moreuser actuatable devices operatively associated therewith.

According to another form of the invention, a patient bed includes abase, a support frame system supported by the base, and a controlsystem. The support frame system includes a deck frame, with a pivotalhead-end section. The control system includes an actuator to pivot thehead-end section and is adapted to control the speed of the actuatorand, further, to selectively increase the speed of the actuator to pivotthe head-end section at a greater speed.

In one aspect, the deck support further includes a pivotal seat sectionand a pivotal foot section, with the control system further including anactuator to selectively pivot the seat section and an actuator toselectively pivot the foot section. The control system is adapted tocontrol the speed of the actuators and, further, to selectively increasethe speed of at least one of the actuators to pivot the head section,the seat section, or the foot section at a greater speed.

In one aspect, the control system includes a user actuatable device,with the control system selectively increasing the speed of the actuatorwhen the user actuatable device is actuated. For example, the useractuatable device may comprise a button, a touch pad, a touch screen, ahandle or pedal. When the user actuatable device comprises a touchscreen, the touch screen may include an icon associated with theactuator, wherein when the icon on the touch screen is touched the speedof the actuator is varied.

In another aspect, control system increases the voltage to the actuatorto thereby increase the speed of the actuator. Further, the controlsystem may be adapted to couple to a remote power supply, which has avoltage, with the control system converting the voltage supplied by theremote power supply to deliver a first voltage to the actuator. Further,the control system converts the voltage of the remote power supply to asecond voltage to deliver a second voltage to the actuator wherein thesecond voltage is greater than the first voltage to increase the speedof the actuator and thereby increase the speed of the movement of thehead-end section.

In another aspect, the bed includes a battery. The control system isadapted to couple to a remote power supply and is adapted to convert thevoltage of the remote power supply into a first voltage and to deliverthe first voltage to the actuator. Further, the control system uses thevoltage of the battery to increase the first voltage to the actuator.For example, the control system delivers about 12 volts to the actuatorand selectively increases the voltage to the actuator from about 12volts to about 24 volts to thereby increase the speed of the head-endsection.

In a further aspect, the control system increases the voltage until thehead-end section is moved to a substantially horizontal position. Forexample, the control system further comprises a sensor, which detectswhen the head-end section is moved to a substantially horizontalposition.

In another form of the invention, a patient bed includes a base, asupport frame system for supporting a lying surface on the base, and anelevation mechanism for raising or lowering the support frame systemrelative to the base. The bed further comprises a control system, whichincludes one or more actuators for activating the elevation mechanism toraise or lower the support frame system relative to the base. Thecontrol system is powered by (1) a remote power supply or (2) at leastone battery. When powered by the remote power supply the control systemoperates the actuator independent of the battery. When powered by thebattery, the control system operates the actuator in dependent of theremote power supply.

In a further aspect, when there is a loss of power in the remote powersupply, the control system is powered by the battery.

In a further aspect, the control system recharges the battery with theremote power supply.

In another form of the invention, a patient bed includes a base, asupport frame system for supporting a lying surface relative to thebase, and an elevation mechanism. The elevation mechanism includes afirst pair of arms and a second pair of arms, which are mounted relativeto the support frame system and the base. Each of the arms has an upperarm portion and a lower arm portion. The upper arm portions arepivotally mounted to the respective lower arm portions and to the framesystem. The lower arm portions are pivotally mounted to the base. Theupper arm portions are biased upwardly relative to the lower armportions by a spring force. The elevation mechanism further includes alinear actuator cooperating with each pair of the arms, which isselectively actuated to pivot the lower arm portions relative to thebase. In addition, the lower arm portions are linked to the upper armportions by linkages, which are configured to pivot the upper armportions relative to the lower arm portions when the lower arm portionspivot about the base wherein the lower arm portions pivot the upper armportions when the lower arm portions are pivoted by the actuator tothereby raise or lower the support frame system relative to the base.

In one aspect, the support frame system is located between two verticalgenerally parallel planes when the support frame system is lowered tothe base, and wherein the elevation mechanism moves the support framesystem relative to the base and is configured to generally maintain thesupport frame system between the two vertical planes when moving thesupport frame system.

In another aspect, the base includes a longitudinal axis and theelevation mechanism is configured to raise or lower the support framesystem relative to the base with a longitudinal deviation relative tothe longitudinal axis of less than about 1 inch. In a further aspect,the deviation is less than about ¾ of an inch, and, more optimally, lessthan about ½ inch.

In yet another aspect, the upper arm portions of at least one pair ofthe arms are pivotally mounted relative to the support frame system at apair of pivot joints, which move in a sinusoidal path when the supportframe system is moved relative to the base by the elevation mechanism.For example, the sinusoidal path has a maximum amplitude of about 1inch, or more optimally a maximum of ½ inch.

In a further aspect, each of the lower arm portions is connected to arespective upper arm portion by first and second linkage. Further, eachof the first and second linkages includes a longitudinal extent, withthe longitudinal extent of each first linkage being non-parallel withthe longitudinal extent of its respective second linkage.

In yet other aspects, the lower arm portions are pivotally mounted tothe base about a first pivot axis. The first and second linkages of eachof the lower arm portions are pivotally mounted to the base about asecond pivot axis spaced from the first pivot axis. The opposed ends ofeach of the first and second linkages are being pivotally mounted to theupper arm portion offset from the pivot axes of the upper arm portionsrelative to the lower arm portions.

According to yet another aspect, each of the arms includes a spring,such as a torsion spring, for applying the biasing force to the upperarm portions of the respective arm.

In another form of the invention, a patient bed includes a base, apatient support mounted for movement relative to the base, an elevationmechanism for raising or lowering the patient support relative to thebase, and wherein the elevation mechanism is configured to move thepatient support relative to the base in a manner to generally maintainthe patient support between two vertical parallel planes when moving thepatient support relative to the base.

In one aspect, the elevation mechanism is configured to raise or lowerthe patient support relative to the base with a maximum longitudinaldeviation of less than about 1 inch and, more optimally, of less about ½inch.

In another form of the invention, a patient bed includes a base, asupport frame system for supporting a lying surface relative to thebase, and an angle sensor mounted to a component of the base or thesupport frame system. The angle sensor measures an angle of thecomponent based on gravity wherein the angle sensor may detect theangular orientation of the component independent of any frame ofreference.

In one aspect, the angle sensor comprises a gravitational accelerometer.

In another aspect, the support frame system includes a deck frame, whichincludes a head-end section and a foot-end section, with the sensorlocated at the head-end section or the foot-end section.

In addition the patient bed may include a microcontroller that is incommunication with the sensor.

In another form of the invention, a patient bed includes a base, asupport frame system, and a visual indicator. The support frame systemincludes an intermediate frame and a deck frame supported by theintermediate frame. The deck frame includes a head-end section and afoot-end section, with the head-end section being pivotally mountedrelative to the intermediate frame. The support frame system furtherincludes a side rail with a body. The visual indicator is located on thebody of the side rail adjacent the perimeter of the body so that thevisual indicator provides a visual indication of the angular orientationof the head-end section of the deck frame when the head-end section ispivoted to an inclined position relative to the intermediate frame.

In one aspect, the visual indicator includes a plurality of spaced apartmarkings adjacent the perimeter of the body, with each of the markingsbeing associated with an angle.

The visual indicator may be formed by a membrane applied to the body ormay be molded in the body, for example.

In another form of the invention, an ICU patient bed includes a base anda support frame system supported relative to the base. The support framesystem includes a deck frame, which includes a head-end section, a seatsection, and a foot-end section, and further side rails, a footboard,and a headboard. A display comprising a touch screen is mounted to theheadboard or the footboard or one of the side rails.

In one aspect, the touch screen includes a menu with a plurality oficons.

In another aspect, the bed further includes a control system with agraphical user interface for displaying icons on the touch screen. Forexample, the touch screen may display a function selected from a groupconsisting of apparatus motion, mattress air pressure, patient motion,patient biometrics, scale, bed security, alerts, exit and eventlog/history, help screens, diagnostics, run lights, or door/windows, andmotion sensors.

In a further aspect, the touch screen displays a summary of thepatient's status.

In yet another aspect, the touch screen is located in the footboard. Forexample, the touch screen may be mounted in a console, which is thenmounted at the footboard. For example, the console may be pivotallymounted in the footboard.

In another form of the invention, a patient bed includes a base, apatient support mounted relative to the base, a bed communicationnetwork, and a control system. The control system includes a controlmodule located at the bed, which is in communication with the bedcommunication network and is in communication with one or more devicesat the bed through the bed network for monitoring or controlling the oneor more devices.

For example, the sensor may comprise a sensor, with the control modulemonitoring the status of the bed through the sensor.

In one aspect, the device comprises a patient monitoring device, and thecontrol module monitors the status of the patient through the patientmonitoring device.

For example, the bed network may comprise a serial communicationnetwork, a CAN-based network, Echelon™-based network, or a peer-to-peernetwork. The bed network may comprise a wireless, based network, such asan RF communications network, a Bluetooth® communications network, aninfra-red communications network or an ultrasound communicationsnetwork.

In one aspect, the control module comprises a digital recognition systemthat positively identifies only pre-authorized individuals to operatethe control module. For example, the digital recognition system maypositively identify only pre-authorized individuals to operate thecontrol module based on image or signal or field. For example, thesignal may be generated by an RFID tag. The image may be based on afingerprint, iris, or vein pattern.

The field may be generated by a magnetic device.

In a further aspect, wherein the control module is configured tocommunicate with a remote communication system.

In yet a further aspect, the control module may include a camera, whichprovides visual communication between a patient and a third party, suchas a health care provider.

In another form of the invention, a patient bed includes a base, whichincludes a frame and a plurality of bearing members for moving the baseacross a surface, and a support frame system supported by the base. Thesupport frame system includes an intermediate frame and a deck frame,with the deck frame including a pivotal head-end section, a seatsection, and a pivotal foot-end section. The intermediate frame has alongitudinal extent shorter than the deck frame wherein the intermediateframe longitudinal extent terminates adjacent the foot-end sectionwherein the foot-end section is pivotal relative to the seat sectionindependent of the movement of the seat section.

In one aspect, the bed further includes a control system, which includesa plurality of actuators for selectively pivoting the head-end section,the seat section or the foot-end section independent of the othersections.

In another form of the invention, a frame elevating mechanism includes afirst frame configured to be supported on a floor surface, a secondframe oriented above the first frame and configured to be moveablysupported by the first frame, and first and second drive mechanismscapable of operating at variable speeds for selectively adjusting anelevation of the second frame. The first drive mechanism controls theelevation of a first end of the second frame. The second drive mechanismcontrols the elevation of a second end of the second frame. In addition,the first drive mechanism is configured to initially operate at a firstmaximum operating speed, and the second drive mechanism is configured toinitially operate at a second maximum operating speed that issubstantially equal to the first maximum operating speed. At least oneangle sensor is located on the second frame for determining an angle ofinclination of the second frame. A control unit for selectivelycontrolling the elevation of the second frame is also provided whereinduring a change in elevation of the second frame, the control unitrepeatedly compares a starting angle of inclination of the second frameto a present angle of inclination of the second frame. If notsubstantially equal, the control unit adjusts the operating speed of oneof the drive mechanisms to compensate.

In another form of the invention, a method of changing an elevation of aplatform subject to an uneven distribution of load while maintaining anangle of inclination of the platform includes determining a startingangle of inclination of the platform by means of at least one anglesensor located on the platform, activating first and second drivemechanisms configured to change an elevation of first and second ends ofthe platform, respectively, with the first and second drive mechanismsconfigured to initially operate at substantially equivalent maximumspeeds, and determining a present angle of inclination of the platformby means of the at least one angle sensor. The starting angle ofinclination is compared to the present angle of inclination. If notequal, the speed of one of the drive mechanisms is adjusted tocompensate. It is then determined whether the platform has obtained adesired elevation, which is repeated until the desired elevation isobtained. The drive mechanisms are then stopped upon obtaining thedesired elevation.

In another form of the invention, a patient bed includes a base, apatient support, and an elevation mechanism for selectively raising orlower the patient support relative to the base. The patient supportincludes a support system frame and a side rail, which is movablebetween a raised position and a lowered position. The base has aplurality of bearing members for moving the base and the patient supportacross a surface, with each of the bearing members including a brakeoperatively associated therewith. The bed also includes a power supplyand a control system for controlling the elevation mechanism. Inaddition, the bed includes a detection system, which is in communicationwith the control system and is adapted to sense the status of theelevation system, the power supply, the position of the side rail, thebrakes of the bearing members, or the control system. The detectionsystem is in communication with a display, which displays the statusdetected by the detection system.

In one aspect, the detection system includes at least one sensor sensingthe status of the elevation system, the power supply, the position ofthe side rail, or the brakes of the bearing members.

In a further aspect, the detection system includes a data logger forlogging the status, with the display displaying a scrolling text of thestatus data logged by the data logger.

In yet another aspect, the bed also includes a driver for selectivelymoving the base across a support surface and a handle mounted to thebed. The control system adjusts the speed of the driver as a function ofan actuating input at the handle. For example, the actuating input mayinclude a force applied on the handle, a signal from a switch at thehandle, or a signal from a heat sensor at the handle.

BRIEF DESCRIPTION OF DRAWINGS

The detailed description particularly refers to the accompanying figuresin which:

FIG. 1 is a right perspective view of a patient support apparatus inaccordance with an embodiment of the present invention;

FIG. 2 is a right side view of the patient support apparatus of FIG. 1;

FIG. 3 is a front side view of the patient support apparatus of FIG. 1wherein a right push handle is in a working position and a left pushhandle is in a stored position;

FIG. 4 is a right perspective view of the patient support apparatus ofFIG. 1 wherein a seat and a foot portion of a support deck arearticulated;

FIG. 5 is a right perspective view of the patient support apparatus ofFIG. 4, wherein a head portion of the support deck if furtherarticulated and wherein a load-bearing frame generally mounted atop anintermediate frame of the patient support apparatus via one or more loadcells is not shown to reveal one of the load cells;

FIG. 6 is a right perspective view of the patient support apparatus ofFIG. 5, wherein a left head-end and a right foot-end side rail are inrespective retracted positions;

FIG. 7 is a right perspective view of the patient support apparatus ofFIG. 6, further comprising a lying surface;

FIG. 8 is a right perspective view of the patient support apparatus ofFIG. 1, further comprising a lying surface and wherein head-end andfoot-end side rails are in respective retracted positions;

FIG. 8A is a schematic drawing of the control system architecture of thebed of the present invention;

FIG. 9 is a right perspective view of a base frame assembly of thepatient support apparatus of FIG. 1, showing attachment of a wheelsystem thereto;

FIG. 10 is a right perspective view of the base frame assembly of FIG.9, showing attachment of a further drive wheel system thereto;

FIG. 11 is a right perspective view of the base frame assembly of FIG.9, showing attachment of a further braking system thereto;

FIGS. 12A to 12C are right perspective views of an indicator system forthe braking system of FIG. 11, shown in steer, neutral and brakeindication respectively;

FIGS. 13A to 13C are right perspective views of the braking system ofFIG. 11 in a steer, neutral and brake position respectively, showing indetails A and B central and lateral levering mechanisms thereofrespectively;

FIGS. 14A to 14C are right perspective views of the braking system ofFIG. 13A in override mode, wherein the central levering mechanism is ina steer position and wherein an override pedal is in a brake, neutraland steer position respectively;

FIGS. 15A to 15C are right perspective views of the braking system ofFIG. 13B in override mode, wherein the central levering mechanism is ina neutral position and wherein an override pedal is in a brake, neutraland steer position respectively;

FIGS. 16A to 16C are right perspective views of the braking system ofFIG. 13C in override mode, wherein the central levering mechanism is ina brake position and wherein an override pedal is in a brake, neutraland steer position respectively;

FIGS. 17A to 17D are right perspective views of an intermediate framemounted via an elevation mechanism to the base frame of FIG. 9, whereinthe intermediate frame is in a flat and elevated position, aTrendelenburg position, a reverse Trendelenburg position, and a flat andlowered position, respectively;

FIGS. 18A to 18C are right side views of an intermediate frame mountedvia an elevation mechanism to the base frame of FIG. 9, wherein theintermediate frame is in a flat and elevated position, a Trendelenburgposition, and a flat and lowered position, respectively;

FIG. 19 is a top side view of an intermediate frame mounted via anelevation mechanism to the base frame of FIG. 9, wherein theintermediate frame is in a flat and lowered position;

FIGS. 20A to 20C are right side views of an intermediate frame, loadbearing frame and deck support mounted via an elevation mechanism to thebase frame of FIG. 9, wherein the intermediate frame, load bearing frameand deck support are in a flat and elevated position, a reverseTrendelenburg position, and a lowered reverse Trendelenburg position,respectively;

FIG. 21 is a exploded right perspective view of the intermediate frame,elevation mechanism and base frame of FIG. 17A, showing aninterconnection of the elevation mechanism's elevation arms between theintermediate frame and the base frame;

FIGS. 22A and 22B are exploded perspective views of the head-end andfoot-end elevation arms of FIG. 21, respectively;

FIG. 23 is an exploded perspective view of the head-end elevation armsof FIG. 22A, showing assembly of mounting covers thereto;

FIGS. 24A and 24B are side views of an elevation mechanism geometry inaccordance with one embodiment of the present invention, wherein aprogression of the elevation mechanism geometry is shown through variouspositions thereof, one of which being superimposed on an exemplary liftarm mechanism in FIG. 24A;

FIGS. 25A to 25D are side views of the elevation mechanism geometry ofFIGS. 24A and 24B shown at respective positions;

FIG. 26 is an exploded right perspective view of the intermediate frameof FIG. 21, showing attachment of load cells and partial attachment of ahead-end operating console thereto;

FIGS. 27 and 28 are partial exploded front perspective views of thehead-end operating console of FIG. 26;

FIGS. 29A and 29B are respectively exploded and detailed exploded viewsof an assembly of a head-end control panel to the head-end operatingconsole of FIGS. 26 to 28;

FIG. 30 is an exploded view of an operating handle of the head-endoperating console as shown in FIGS. 27 and 28;

FIG. 31 is an exploded right perspective view of a load bearing frame asit is mounted to the load cells of the intermediate frame of FIG. 26;

FIG. 32 is a right perspective view of a deck support mounted to theload bearing frame of FIG. 31, showing an assembled head portion, seatportion and a leg portion of the deck support;

FIG. 33 is an exploded right perspective view of an assembly of the headand seat portions of the deck support of FIG. 32 to the load bearingframe;

FIG. 34 is an exploded right perspective view of an assembly of the headand foot portions of the deck support of FIG. 32 to the load bearingframe;

FIG. 35 is a rear left bottom perspective view of an actuation of thehead portion of the deck support of FIG. 32 relative to the load bearingframe;

FIG. 36 is a right perspective view of an actuation of the seat portionof the deck support of FIG. 32 relative to the load bearing frame, aseat portion cover being omitted for clarity;

FIG. 37 is a right perspective view of an assembly of a leg portionhousing of the deck support leg portion of FIG. 32 to the seat portionand load bearing frame;

FIG. 38 is a right perspective view of the deck support of FIG. 32, aleg portion cover being omitted to show constituents of an internalhousing thereof;

FIG. 39 is a left perspective view of the deck support leg portion ofFIG. 32;

FIGS. 40A and 40B are right perspective views of a barrier system of thepatient support apparatus of FIG. 1 in fully extended and fullyretracted positions respectively, the barrier system comprising aheadboard, a footboard, and retractable head-end and foot-end siderails;

FIG. 41 is an exploded right perspective view of an assembly of thehead-end side rails of FIG. 40 to the support deck head portion of FIGS.32 and 33, the cover thereof omitted for clarity;

FIGS. 42 and 43 are respective exploded views of an internal assembly ofthe head-end side rail of FIG. 41 and an internal assembly of head-endside rail control panels thereof;

FIG. 43A is an elevation view of a side rail of the present inventionincorporating covers for sealing the joints or gaps between theinterface panels and the side rail body;

FIG. 43B is an enlarged perspective view of the side rail of FIG. 43A;

FIG. 43C is an enlarged cross-section taken along line XXXXIIIC-XXXXIIICof FIG. 43A;

FIG. 43D is an exploded perspective view of the side rail of FIG. 43B;

FIG. 44 is an exploded right perspective view of an assembly of thefoot-end side rails of FIG. 40 to the load bearing frame of FIG. 31;

FIGS. 45 and 46 are respective exploded views of an internal assembly ofthe foot-end side rail of FIG. 44 and an assembly of a foot-end siderail control panel coupled thereto;

FIG. 45A is an elevation view of a visual indicator that can be providedor formed on a side rail to provide a visual indication of the angle ofthe head-end section of the deck frame when the head-end section isinclined;

FIGS. 47A to 47D are inner side views of the foot-end side rail of FIG.44 in positions ranging from a fully extended position (FIG. 47A) to afully retracted position (FIG. 47D);

FIGS. 48A to 48D are inner perspective views of the foot-end side railof FIG. 44 in positions ranging from a fully extended position (FIG.48A) to a fully retracted position (FIG. 48D);

FIG. 49 is a top plan view of a side rail showing a guiding mechanismthereof in accordance with one embodiment of the present invention;

FIG. 50 is a side view of a side rail showing a locking mechanismthereof in accordance with one embodiment of the present invention;

FIGS. 51A and 51B are outer perspective views of the footboard of FIG.40, showing a footboard control console thereof in coplanar and tiltedpositions respectively;

FIG. 52 is an inner perspective view of the footboard of FIG. 40 showingthe footboard control console in the tilted position shown in FIG. 51B;

FIGS. 53 and 54 are respective exploded views of an assembly of thefootboard of FIGS. 50 to 51 and an assembly of the footboard controlconsole coupled thereto, respectively;

FIG. 55 is a diagrammatic view of an outer control interface provided byone of the head-end side rail control panels of FIG. 43;

FIG. 56 is a diagrammatic view of an inner control interface provided byone of the head-end side rail control panels of FIG. 43;

FIG. 57 is a diagrammatic view of an outer control interface provided byone of the head-end side rail control panel of FIG. 46 as well as by thehead-end control panel of FIGS. 29A and 29B;

FIG. 58 is a diagrammatic view of a control interface provided by thefootboard control console of FIG. 54;

FIGS. 59A to 59D are diagrammatic views of exemplary screen shotsprovided by an LCD display of the control interface of FIG. 58;

FIG. 60 is a diagrammatic representation of an emergency system forincreasing a voltage applied to one or more bed positioning actuators,thereby increasing a velocity thereof, when a user selects a specificpositioning function on a given control panel;

FIG. 61 illustrates an actuator/motor control system;

FIG. 62 illustrates a load cell system;

FIG. 63 illustrates an embodiment comprising a scale or weigh subsystem;

FIG. 64 depicts the functional block diagram of an accelerometer used inan embodiment of the present invention;

FIG. 65 displays a tilt sensor circuit according to an embodiment of thepresent invention;

FIG. 66 depicts a horizontal patient support with a load according to anembodiment of the present invention;

FIG. 67 depicts an incline patient support with a load at angle Daccording to an embodiment of the present invention. FIG. 27 illustratesa part of a user interface embedded into a patient support according toan embodiment of the present invention;

FIG. 68 illustrates part of a user interface according to one embodimentof the present invention intended for use by a patient;

FIG. 69 illustrates the window content of a step in a series ofuser-patient support interaction processes displayed on a detacheddevice such as a general purpose computer according to one embodiment ofthe present invention;

FIG. 70 illustrates part of a user interface according to one embodimentof the present invention intended for use by a patient;

FIG. 71 illustrates a motor control and drive system according to oneembodiment of the present invention;

FIG. 72 illustrates an interface controller according to one embodimentof the present invention;

FIG. 73 illustrates a scale subsystem according to one embodiment of thepresent invention;

FIG. 74 illustrates a power supply system according to one embodiment ofthe present invention;

FIG. 75 illustrates a communication interface according to oneembodiment of the present invention;

FIG. 76 illustrates a motor speed compensation circuit embodying theinvention;

FIG. 77 is a flow chart of an algorithm utilized by the motor speedcompensation circuit according to one embodiment of the invention; and

FIG. 78 is a flow chart of an algorithm utilized by the motor speedcompensation circuit according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The bed of the present invention comprises structural elements (SectionI), power and control systems (Section II); structural informaticssystems (Section III); user-bed communication interfaces (Section IV);and bed-network communications systems (Section V).

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention pertains.

I. Structural Elements

A hospital bed, generally referred to using the numeral 100 and inaccordance with an embodiment of the present invention, is generallyshown in FIGS. 1 to 8. For the purpose of this description, the bed 100may be defined to include a head-end 102 and an opposing foot-end 104,respectively defining the ends of the bed 100 at which a user's head andfeet may be positioned, and right and left sides 106 and 108 joiningthese ends.

The bed 100 generally includes a frame system that forms a patientsupport and a base. In the illustrated embodiment, the base comprises abase frame 200 (e.g. see FIGS. 9 to 16); though it should be understoodthat other bases may be used, including any structure that supports thepatient support, including a plurality of legs that extend downwardlyfrom the patient support. The patient support comprises a support framesystem that includes an intermediate frame 400 (e.g. see FIG. 26)operatively coupled to the base via an elevation system 500 configuredto raise and lower the support frame system relative to the base (e.g.see FIGS. 17 to 25) and thereby orient the intermediate frame 400 invarious positions. As noted below, base frame 200 forms a movable basefor the support frame system.

In general, the base frame 200 comprises a transport system including aset of bearing members, such as wheels, casters 202 or the like,allowing for motion and maneuverability of the bed 100. An optionaldrive wheel system 204 (e.g. see FIG. 10) may also be provided tofacilitate movement of the bed 100 by an operator. A braking system 206,optionally comprising an emergency override system 208 (e.g. see FIGS.11 to 16), may also be provided. A head-end control module 450 (e.g. seeFIGS. 27 to 29), as well as various other control modules, panels and/orconsoles described further below, is generally provided on theintermediate frame 400 and provides various controls, such as pushhandles 451 (detailed in FIG. 30) for the above and other such systems,described below.

The support frame system also comprises a load bearing frame 600,disposed atop the intermediate frame 400 via intermediary load cells 602or the like (e.g see FIG. 31), which are configured to sense and/ormonitor a load positioned on the bed 100. In particular, a deck support700 fitted to the load-bearing frame 600 (e.g. see FIGS. 32 to 39) maybe provided upon which may be mounted a lying surface 800, such as amattress or the like, for receiving a user of the bed 100 thereon. Assuch, as will be discussed further below, as the weight of a user isapplied to the lying surface 800, or again shifted thereon, the loadcells 602 may detect this weight.

As illustrated in FIGS. 1 to 6 and 32, for example, the deck support 700generally comprises a head or Fowler section 702, toward the head-end102 of the bed 100, which is pivotally coupled to a seat/thigh or KneeGatch section 704, itself pivotally coupled to a foot section 706,toward the foot-end 104 of the bed 100. Each of the head, seat/thigh andfoot sections 702, 704, and 706 are configured to articulate the decksupport 700 between a plurality of positions, such as for example, asubstantially horizontal position (FIGS. 1 to 3 and 32), a legs-downposition (FIG. 4), a substantially seated position (FIGS. 5 and 6), etc.The lying surface 800, fitted on the deck support 700, is adapted tomove therewith thereby also comprising a head or Fowler section 802, aseat/thigh or Knee Gatch section 804, and a foot section 806 that may beoriented with the deck support's various sections, as seen for examplein FIGS. 7 and 8. The lying surface may comprise any one of a variety ofmattresses, including for example, Gaymar, or foam or air mattress. Thedeck support 700 and lying surface 800 will be described in greaterdetail below.

The bed 100 may further comprise a barrier system 900, which may includeany combination of head-end side rails 902, foot-end side rails 904, aheadboard 906 and a footboard 908. The various side rails 902, 904 maybe adjustably coupled to the frame system and moveable relative theretobetween fully extended and fully retracted positions. For example, inFIGS. 1 to 5 and 40A, both the head-end side rails 902 and foot-end siderails 904 are shown in their fully extended positions, whereas in FIGS.6 and 7, the left head-end side rail 902 and the right foot-end siderail 904 are shown in their retracted positions. In FIGS. 8 and 40B, allside rails 902, 904 are shown in their fully retracted positions. Thebarrier system 900 will be described in greater detail below.

The bed 100 may also comprise a control system 1000 (FIG. 8A),comprising one or more control interfaces (e.g. head-end panel 453,footboard console 976, side rail panels 990, 993, 995, remote panels,etc.) and/or devices (e.g. push handles 452 for controlling power to thedrive wheel mechanism 204, etc.) disposed on or near the bed 100,providing a user and/or patient control access to the bed's 100 variousfeatures and/or commands, which may include various functions of patientsupport. The control system 1000, and other patient support functionsrequiring power, are powered by an AC plug connection to a remote powersupply, such as a building outlet, or a battery supported by the framesystem, as will be discussed in greater detail below. In one embodiment,the control system 1000 may be configured to operate and monitor aplurality of linear actuators provided to move, for example, theintermediate frame 400 relative to the base frame 200 (e.g. to controlthe elevation system 500), to move the head, seat and foot sections 702,704 and 706 of the deck support 700 to provide various lying surfacepositions. Operation of the bed's braking system 206 and/or optionaldrive wheel system 204, and/or other such systems, may also beconsidered herein, as will be readily understood by the person skilled,without departing from the general scope and nature of the presentdisclosure.

Furthermore, a structural informatics system, which may comprise adiagnostic and control system component, may also be provided, whereinthe bed 100 comprises a plurality of electronic elements including forexample, load sensors, tilt or angular sensors (e.g. inclinometers,etc.), linear sensors, temperature sensors, electronic controls andkeyboards, wiring actuators for adjusting bed angles and the like, inaddition to other electronic elements. For example, with reference tothe illustrative embodiments depicted in the appended Figures, loadsensors may include, but are not limited to, load frame load cells 602(e.g. see FIG. 26) for detecting and/or monitoring a load distributionand variation on the deck support 700, a drive handle load cell 462(e.g. see FIG. 27) for communicating a pressure applied to the drivehandles 451 in view of controllably operating the optional drivemechanism 204 (e.g. see FIG. 10). Furthermore, tilt or angular sensorsmay include, but are note limited to, a base frame sensor 203 (e.g. seeFIG. 11), a load frame sensor 622 (e.g. see FIG. 31), a head sectionsensor 758 and a seat section sensor 772 (e.g. see FIG. 33), a footsection sensor, a side rail lock mechanism sensor 951 for detectingwhether a given side rail 902, 904 is secured in a desired position(e.g. see FIGS. 42 and 45), and other such sensors for usedindependently or in combination with any number of the above exemplarysensors. Additional sensors may include sensors that detect when devicesare mounted to the bed, which sensors communicate to control system whena device is coupled to the bed. Further, the control system may detectand identify the device and, further, generate a signal to one or moreof the displays to display an icon or display associated with thedevice, which can provide an input/control for that device at thedisplay. In this manner, the control system can update the displays toreflect any devices that are mounted to the bed.

Also, a number of monitoring switches, such as brake status and/oroverride status switches 314 and 291 respectively, (e.g. see FIG. 11), aside rail position status switch, and other such switches may beprovided and used independently, or again in combination with any numberof the above or other such switches and/or sensors.

The diagnostic and control system can enable the specific control ofeach of these electronic elements for desired operation thereof andfurther can enable the monitoring of the operating conditions of theseelectronic elements and additional bed conditions. The diagnostic andcontrol system further enables the evaluation and determination of theexistence of one or more faults relating to the operation of the bed100.

The Frame System

As discussed hereinabove, the bed 100 generally comprises a frame systemcomprised of a base frame 200 and a support frame system comprising anintermediate frame 400 operatively coupled to base frame 200 via anelevation system 500 configured to raise and lower the intermediateframe 400 relative to the base frame 200 and thereby orient theintermediate frame 400 in various positions. The support frame systemfurther includes load-bearing frame 600 mounted on the intermediateframe 400 via a set of load-cells 602 or the like, atop which is mountedthe deck support 700 and lying surface 800. A barrier system 900 isfurther coupled to various components of the frame system and/or decksupport 700, as described further below.

As stated above, the base frame 200 comprises a transport systemincluding a set of wheels, such as casters 202 or the like, allowing formotion and maneuverability of the bed 100. An optional drive wheelsystem 204, operated for example using push handles 1004, may also beprovided to facilitate movement of the bed 100 by an operator. A brakesystem 206, optionally comprising an emergency override system 208, mayalso be provided.

The elevation system 500, which generally comprises lift arms 502interconnecting the base frame 200 to the intermediate frame 400,comprises in one embodiment, a series of linear actuators 504 configuredto provide power to actuate the lift arms 502 and in turn raise andlower the intermediate frame 400 relative to the base frame 200. Asexplained in more detail below, lift arms 502 and linear actuators 504are configured to position the intermediate frame 400, and ultimatelythe deck support 700 and lying surface 800 mounted thereon, in at leastsome of the following positions: a raised or upper substantiallyhorizontal position wherein the intermediate frame 400 is at leastpartially raised above the base frame 200 (e.g. see FIGS. 1 to 8, 17A,18A and 20A); a Trendelenburg position wherein a head-end 402 ofintermediate frame 400 is lower than a foot-end 404 thereof (e.g. seeFIGS. 17B and 18B); a Reverse Trendelenburg position wherein thefoot-end 404 of intermediate frame 400 is lower than the head-end 402thereof (e.g. see FIGS. 17C, 20B and 20C, wherein the bed 100 in FIG.20C is in a lowered Reverse Trendelendburg position); and a loweredsubstantially horizontal position wherein the intermediate frame 400 islowered adjacent to the base frame 200 (e.g. see FIGS. 17D and 18C). Oneskilled in the art will appreciate that the positions shown in theabove-referenced Figures are exemplary positions and that theintermediate frame 400 may be positioned in a wide variety of positionsrelative to the base frame 200.

As presented above, the various sections of the deck support 700 andlying surface 800 may be moved relative to the intermediate and/orload-bearing frames 400, 600 to move a user on the bed to variouspositions. For example, it may be required to configure the lyingsurface 800 of the bed 100 in a configuration that is designed to assista caregiver in providing CPR to the patient supported thereon. In oneexample, a CPR configuration is defined by placing the head, seat andfoot sections 702, 704 and 706 of the deck support 700 in a generallylinear relationship. In one embodiment, the bed can be placed in thispre-defined CPR configuration via the control system 1000, which cancomprise one or more control panels (e.g. see FIG. 55) configured tocontrol a number of linear actuators operatively disposed to actuate thevarious sections of the deck support 700 to achieve the CPRconfiguration.

Other positions may also be considered useful in providing care to apatient positioned on the bed 100. For instance, with reference to FIG.8, the head section, seat section and foot section 702, 704 and 706 maybe positioned in a substantially linear relationship to provide asubstantially flat lying surface 800. In one embodiment, the headsection 702, seat section 704 and foot section 706 are placed in thislinear relationship by the control system 1000 in response to a singleuser actuatable device, such as a button, being depressed on one of thecontrol system's various control panels (e.g. see FIG. 55).

With reference to FIGS. 5 to 7 and 33 to 35, the head section 702 can berotated about pivot 708 such that a head-end 710 of the head section 702is raised relative to a foot-end 712 thereof. For example, the head-end710 may be raised by the control system 1000 controlling an actuator 714(FIGS. 34 and 35) to further extend a cylinder 716 of this actuator 714and thereby raise the head-end 710. In one embodiment, the head section702 is raised by the control system 1000 in response to a first useractuatable device, such as a button, being depressed on one of thecontrol system's various control panels (e.g. see FIG. 57), and loweredby the control 1000 system in response to a second user actuatabledevice, such as a second button, being depressed on this same panel.

Furthermore, with reference to FIGS. 4 to 7, 33 and 36, the seat section704 can be similarly rotated about pivot 718 such that its foot-end 720is raised relative to its head-end 722. The seat section's foot-end 720may be raised by the control system 1000 controlling an actuator 724(FIG. 33) to further extend a cylinder 726 of the actuator 724 therebyraising the seat section's foot-end 720. In one embodiment, the seatsection 704 is raised by the control system 1000 in response to a firstuser actuatable device, such as a first button, being depressed on oneof the control system's various control panels (e.g. see FIG. 57), andlowered by the control 1000 system in response to a second useractuatable device, such as a second button, being depressed on this samepanel.

Also, with reference to FIGS. 4 to 7 and 34, the foot section 706 can besimilarly rotated about pivot 728 such that its foot-end 730 is loweredrelative to its head-end 732. The foot section's foot-end 730 may belowered by the control system 1000 controlling an actuator 734 toretract a cylinder 736 of the actuator 734 (FIG. 34) thereby loweringthe foot section's foot-end 730. In one embodiment, the foot section 706is lowered by the control system 1000 in response to a first useractuatable device, such as a first button, being depressed on one of thecontrol system's various control panels (e.g. see FIG. 57), and loweredby the control 1000 system in response to a second user actuatabledevice, such as a button, being depressed on this same panel.

The Base Frame

With reference to FIG. 9, the base frame 200 generally comprises a pairof side frame rails 210, 212 and two or more transversal frame rails, asin rails 214, 216 and 218 connected to, and extending between, the sideframe rails 210 and 212. For example, in the embodiment illustrated inFIG. 8, the base frame 200 includes right and left side frame rails 210and 212 respectively, a head-end rail 214, a foot-end rail 216 and anintermediate rail 218. These rails generally provide the foundation uponwhich the bed 100 is built. In addition, base frame 200 may include abase frame cover 200 a, which may be molded from a polymeric material orcast aluminum, for example. Base frame cover 200 a covers and protectsone or more the various components supported or mounted to the rails. Inaddition, base frame cover 200 a may be formed as a monolithic part tofacilitate cleaning and disinfection, as described more fully below.

In order for the bed 100 to be mobile to enable transport of the bed 100and/or patient from one location to another, a plurality of bearingmembers, such as wheels or caster devices, including casters or casterwheels 202, may be provided to enable bed mobility. In this particularembodiment, four casters 202 are provided and pivotally mounted to thebase frame 200 by means of respective mounting brackets 220 secured in aconventional manner to the corners of the base frame 200. Further, eachcaster includes operatively associated therewith a brake, which are wellknown in the art and available, for example, from Tente.

In one embodiment, the base frame 200 further comprises a sensor 203,such as an inclinometer or the like (e.g. see FIG. 11), for detectingand/or monitoring an inclination/orientation of the base frame 200. Aswill be described in greater detail below, data acquired using this andother such sensors disposed on various parts of the bed can be used incalculating and monitoring various characteristics of the bed 100 and/orof a patient lying thereon. As will be apparent to the person skilled inthe art, the sensor can be mounted elsewhere on the base frame 200without departing from the general scope and nature of the presentdisclosure.

Optional Drive Wheel Mechanism

In one embodiment, for example illustrated in FIG. 10, the bed 100further comprises an optional motorized system for driving the bed 100.For instance, the bed 100 may be equipped with a drive wheel system 204to enable motorized driving of the bed 100 from one location to another.According to this embodiment, a drive wheel support assembly 222 isprovided and configured to enable a drive wheel 224 to move between aretracted position, wherein the drive wheel 224 is tucked within thebase frame 200, and a driving position, wherein the drive wheel 224 islowered for engagement with the floor to facilitate movement of the bed100. In particular, the drive wheel 224 may be urged by a springmechanism 226 into engagement with the floor with sufficient force toaccommodate undulations in the floor surface, namely to maintainsufficient frictional engagement with the floor to provide asubstantially continued and smooth driving of the bed 100 along thefloor surface.

FIG. 10 illustrates the drive wheel support assembly 222 as it ismounted on the base frame 200 of the bed 100. In this illustrativeembodiment, the support assembly 222 comprises a housing 228, which issecured to the head-end rail 214 via mounting brackets 229 thereof andis used for housing the drive system's control circuitry 230 (e.g. theZoom drive circuitry described below, or any other such drive systemcircuitry), a drive wheel support bracket 232 pivotally coupled to thehousing 228 via a torsion spring-loaded axle 234, i.e. providing thespring mechanism 226 introduced above, and a drive wheel actuator 236pivotally mounted to the intermediate rail 218 via mounting bracket 238thereof and drivingly interconnecting the support bracket 232 thereto.

The support bracket 232 generally comprises a pair of substantiallyparallel longitudinal side flanges 240 each oriented in a plane parallelto a longitudinal axis of the base frame 200, interconnected by wallmembers 242 and 244. Coupling ears 246 extending longitudinally towardthe foot-end rail 216 provide coupling holes 248 configured to receivethe axle 234 therein and thereby couple the support bracket 232 to thehousing 228. A torsion spring 250 having oppositely extending legsencircles the axle 234 with one leg of the spring 250 bearing on wallmember 244 and with the other leg bearing against the housing 228. Thestate of the spring 250 when the wheel 224 is deployed is tensioned andis configured to continually urge the support bracket 232counterclockwise about the axle 234.

The mounting bracket 238 generally comprises a pair of parallelextending plates projecting upstandingly away from the intermediate rail218 and including remote from the intermediate rail 218 a pair ofaxially aligned holes for receiving a coupling pin 254, bolt or the liketherein. If desired, crosswise extending members (not illustrated) canbe provided between the plates in order to rigidify the bracket 238.

A drive mechanism 256 for driving the wheel 224 comprises a reversibledrive motor mechanism 258 and a right angle transmission mechanism 260configured to connect the output of the motor 258 to a drive axle onwhich is fixedly secured the drive wheel 224. The drive mechanism 256 issecured to the support bracket 232 between longitudinal side flanges240, the right-angle transmission mechanism 260 being fixedly attachedalong one of the flanges 240 whereas the drive axle and drive wheel 224are rotatably secured to the other via a bearing mechanism 262 or thelike. As a result, when the motor 258 is activated, the output thereofwill effect, through the right angle drive transmission 260, a drivingof the drive wheel 224. A housing 264 may be used to cover the drivemechanism 256, being disposed over same and secured to the supportbracket 232, as shown in FIG. 10.

In this particular embodiment, one of the support bracket's side flanges240 further comprises a bracket 266 configured with an L-shaped slot 268for supporting a pin 270 used to couple the actuator 236 to the supportbracket 232. In particular, the actuator 236 is connected at one end tothe bracket 238, as described above, and at the other end to the pin270. More specifically, the actuator 236 is configured to extend andretract to effect a driving of the support bracket 232 about axle 234 tocause the drive wheel 224 to move toward and away from the floor, namelybetween drive and retracted positions. In this particular embodiment,the actuator 236 includes a reversible motor having a rotatable outputshaft which, upon being rotated, effects an extension and a retractionof a driven member 272. As such, the rotating output of the motor can beconverted into a reciprocal motion of the driven member 272 byconventional means well known in the art. In this particular embodiment,the distal end of the driven member 272 comprises a hole in which isreceived the pin 270.

When the driven member 272 is moved to the retracted position, the pin270 engages an uppermost end of the L-shaped slot 268 to draw thesupport bracket 232 in a clockwise manner about the axle 234 and againstthe urging of the torsion spring 250. Upon operation of the motor toeffect an extension of the driven member 272, the pin 270 is moved todown the L-shaped slot 268 as drive wheel 224 engages the floor. Whenthe drive wheel 224 reaches a recess in the floor, that is a region ofthe floor that is lower than a region engaged by one or more of thecasters 202, the torsion spring 250 will effect a counterclockwisemovement of the support bracket 232 to maintain an engagement of thedrive wheel 224 with the floor with sufficient force so as to permit thedrive wheel 224 to maintain a driving movement of the base frame 200.Simultaneously, the pin 270 will move up in the L-shaped slot 268.Alternatively, when the drive wheel 224 reaches a bump or protuberancein the floor, that is a region of the floor that is higher than a regionengaged by one or more of the casters 202, a clockwise movement of thesupport bracket 232 will be effected against the torsion spring 250 suchthat an engagement of the drive wheel 224 is maintained with the floorwith sufficient force so as to permit the drive wheel 224 to maintain adriving movement of the base frame 200. This motion will thus provide arelatively smooth transition over the bump or protuberance. As above,the pin 270 will move down the L-shaped slot 268 to accommodate for themotion of the support bracket 232. As a result, the spring 250 acts as atype of shock absorber for the drive wheel mechanism to provide asmoother ride.

The person of skill in the art will understand that other drive wheelmechanisms can be considered to provide similar results. For instance,the above L-shaped slot 270 may be linear, curvilinear, or other suchshapes conducive to provide shock absorbing give and extendibility tothe drive wheel 224.

Also, it is to be recognized that the drive wheel actuator 236 could beconnected in a reverse manner to that illustrated in FIG. 10, such thatthe driven member 272 is connected to the bracket 238 via pin 254 whilethe other end of the actuator is coupled to the L-shaped slot 268 ofbracket 266 via pin 270.

It is to be also recognized that the actuator 236 can comprise a drivemotor having a rotatable output shaft rotatable in a single direction ofrotation. In this case, the output shaft of the drive motor, whenrotated, would rotatably drive an elongate double lighted screw shaft onwhich would be provided the driven member 272, here a traveling nut alsohaving a double flighted internal screw thread operatively connected tothe threads on the screw shaft. Upon the nut reaching an end of travelin both lengthwise directions along the length of the screw shaft, acontinued rotation of the screw shaft will effect an automatic crossoverof the operatively mated threads to cause a movement of the nut (anddriven member 272) in the opposite directions.

As will be described further below, activation of the drive wheelmechanism may be achieved using a number of controls provided on oraround the bed 100. For example, in one embodiment, activation of thedrive wheel mechanism is controlled using a same control interface orpanel (e.g. see FIG. 55) used to activate the breaking system 206,described below. For example, the controls may be configured to providethree operating states: a brake state, wherein the casters 202 arelocked (e.g. both from turning and from pivoting), a neutral state,wherein the casters 202 are free to move and driving and maneuverabilityof the bed 100 is achieved manually, and a driving or steering state,wherein the casters 202 are again free to move and wherein the drivewheel mechanism is actuated to bring the drive wheel 224 in operativeengagement with the floor and the drive controls (discussed below) areactivated. It will be understood that a variety of other methods andsystems can be used, as described below, to activate and operate theabove and other such drive wheel systems 204, and that such alternativemethods and systems should not be considered to depart from the generalscope and nature of the present disclosure.

Also, operation of the drive wheel system 204 when activated by theabove controls, may be provided via push handles 451 described furtherbelow, or other such devices as will be readily understood by the personskilled in the art. For instance, in one embodiment, the drive wheelsystem 204, once in drive/steer mode, may be responsive to a forwardand/or backward pressure applied to these handles 451 to impart acorresponding drive to the drive wheel 224. These and other such driveactivation systems will be further described below, in particular, withreference to the illustrative and optional Zoom drive algorithm.

Braking System

The bed may further comprise a braking system 206 to selectivelyimmobilize the bed from moving, or again to selectively immobilize anorientation of one or more of the bed's casters 202. In general, eachcaster 202 can be associated with a common braking mechanism operatedeither manually or by control means provided by the control system 1000.Alternatively, each caster 202 may be associated with a respectivebraking mechanism, or again grouped and associated with respective groupbreaking mechanisms to be operated individually, or via a commonactivation system, as will be readily understood by the person skilledin the art. The caster braking system 206 generally providessimultaneous braking of each caster 202, however, less effective brakingsystems wherein only some of the casters 202 are immobilized may also beconsidered, as will be apparent to the person skilled in the art.

In one embodiment, illustrated for example in FIGS. 11 to 16, thebraking system 206 generally comprises a low force braking system forreducing the force needed by a user to activate and deactivate thebraking system 206. For instance, the bed 100 may comprise apower-assisted or actuated breaking system 206 (e.g. as described below)to facilitate an operation of the bed 100 using various availablesteering and/or braking features of this mechanism. In addition, suchsystems may further comprise one or more hand and/or foot actuatedmanual override mechanisms (e.g. see FIGS. 14 to 16) in the event of apower failure, for example. Contemplated brake system control means mayinclude, but are not limited to, power-assisted hand and/or foot brakes,such as handles or pedals, user actuatable devices, such as a button, atouch screen, and/or a switch, on one or more control panels provided onor near the bed 100, and other such controls powered electrically,hydraulically, pneumatically and/or magnetically, as will be readilyunderstood by the person skilled in the art.

For example, in one embodiment, the user can activate the brakes on oneor more control panels (e.g. see FIGS. 55, 58) located, for example, onthe exterior of the head-end or foot-end side rails 902, 904 and/or onthe head-end structure 450, within the vicinity of the push handles 451,as depicted for example in FIGS. 2 and 3. Access to the brake activationcan also be available on other control panels, including for example, afootboard control console (e.g. see control console 976 in FIGS. 51 to53, and an exemplary interface thereof in FIG. 58), a removable panel,and the like. The positioning of the brake controls on one or morecontrol panels allows the user to more easily access and activate thebraking system 206. For instance, in some embodiments, the positioningof the bed's side rails and/or the positioning of the bed itself (e.g.when the bed is in a lowered position) may impede access to a manualbrake activation pedal or handle (e.g. brake pedal 290 of FIGS. 14 to16). Using controls disposed on one or more control panels, however, thebraking system 206 may still be readily accessed and controlled.

Furthermore, automatic brake control via the control system 1000 canalso provide a safety feature when the system is in a motion lockout,further discussed below. In a total lockout of motion, a lock mechanismprohibits movement functions from being controlled on the controlpanel(s), located for example on the side rails, footboard, pendant andheadboard, etc. The brake can be set during the lockout but, for safetyreasons, preferably cannot be removed at any point during a totallockout.

In one embodiment, the brake control(s) is located proximate the pushhandles 451 and can be engaged or disengaged without removing the user'shands from the handles 451. For example, the bed 100 generally rolls inthe direction guided by the user who is controlling one or more of thepush handles 451. When force is not exerted on the handles 451, thedrive wheel 224 decelerates, and eventually comes to a halt, usuallywithin 4-10 seconds. While the braking system 206 may be used to assistin bed deceleration, it is usually not required, given the bed's slowspeed. Furthermore, if a patient is in the bed 100, use of the brakeduring bed displacement may be jerky and uncomfortable. As such, thebraking system 206 is typically used to secure an immobile bed, similarto a vehicle's hand brake.

When in use, the user engages the braking system 206 which imparts abraking force directly on the casters 202. The brake can be a cam thatpushes on the tire or brake on the axle or separate disk or the wheelitself. The brake system is usable on heavy beds and is adaptable todifferent braking system (ring, wheel, or direct floor pressure).

Furthermore, the casters 202 may comprise brake casters, selectivelyoperated in free rotation and brake modes, or steer/brake castersselectively operated in free rotation mode, pivotally locked mode andbrake mode, wherein actuation of the braking system 206 can implementeither immobilization of one or more casters from rotating (e.g.prohibit displacement of the bed) and/or immobilization of one or morecasters from pivoting (redirecting a displacement of the bed).

For instance, in one embodiment where a drive wheel mechanism isprovided (e.g. such as the drive wheel mechanism 204 described above),the bed 100 may be operated in three states, a braking state wherein thecasters 202 are rotatably and pivotally immobilized, a neutral statewhere the casters 202 are free to move in either direction, and asteering state wherein the casters 202 are still free to move in eitherdirection while a drive wheel mechanism is activated. In anotherembodiment where a drive wheel mechanism is not provided, the bed 100may again be operated in three states, braking and neutral states asabove, and a steering state wherein the foot-end casters 202 (orhead-end casters if the bed 100 is commonly operated from the foot-end)are pivotally immobilized while the head-end casters 202 can movefreely. Other combinations and permutations of the above breaking andsteering options may also be considered, as will be apparent to theperson skilled in the art. Selection of the brake mechanism's state maybe implemented using conventional means, such as a manually operatedhandle and/or pedal, or again via electronic controls (e.g. provided viacontrol panels or the like).

For example, in one embodiment, three push buttons corresponding tobrake, steer and neutral modes are provided on one or more controlpanels (e.g. see FIGS. 55, 58) to selectively operate the braking system206. These buttons may be operatively coupled to one or more actuators,as in actuator 280 of FIGS. 11 to 16, configured to activate ordeactivate the braking system 206. A manual override system 208 may alsobe integrated into the braking system 206 and may include, for example,a manually actuated pedal, as in pedal 290 of FIGS. 14 to 16, or thelike.

The exemplary braking system 206 depicted in FIGS. 11 to 16 will now bedescribed in greater detail. The braking system 206 is generallyconfigured to immobilize the casters 202 from rotating such that adisplacement of the bed 100 is substantially mobilized, and/or frompivoting such that a direction of the caster 202 is stabilized tofacilitate, for example, steering of the bed 100. In the latter case,pivotal braking may be limited, for example, to two of the four casters202 such that an operator of the bed 100 may select an orientation ofthe bed displacement by pivoting two of the casters 202, while using thepivotally locked casters 202 to facilitate this directionaldisplacement.

In the embodiment illustrated in FIG. 11, the braking system 206 isconfigured such that a motorized control of the system 206 is impartedvia a single motor or actuator 280. In particular, the actuator 280,controlled or operated from one or more control means such as brakehandles, user actuatable devices, such as push buttons and the like(discussed further below with reference to the control system 1000), isused to mechanically activate a locking mechanism on each of the casters202. For example, a nurse may activate the brakes from the push handles.In an optimal form, the nurse may activate the brakes without removinghis/her hands from the push handles. A person of skill in the art willunderstand that, although the present embodiment is described asincluding a single actuator 280, such as an electric, a pneumatic, amagnetic, or a hydraulic actuator, for all four casters 202, a similarbraking system 206 could be designed to include one such actuator foreach caster 202, or again, one actuator for each two casters 202 (e.g.an actuator to control the head-end casters 202 and a second actuator tocontrol the foot-end casters 202). Other combinations of actuators forany number of casters may also be contemplated herein without departingfrom the general scope and nature of the present disclosure, as will bereadily understood by the person skilled in the art.

The braking system 206 generally comprises a central levering mechanism282 operatively interconnecting a driven member 284 of actuator 280 tolateral levering mechanisms 286 on each side of the base frame 200 via atransversal shaft 288. The lateral levering mechanisms 286, theright-hand side one of which is illustratively coupled to a manualoverride actuation pedal 290, are themselves configured to actuate thebrake mechanism 292 on each caster 202 via longitudinally extendingbrake actuator bars 294 configured such that a substantially lineardisplacement thereof pivots respective brake actuating levers 295configured to operate the respective brake mechanisms 292 of each caster202. Contemplated brake mechanisms 292 may include, for example, alocking cam or the like configured to selectively immobilize a givencaster 202 from rotating and/or pivoting, depending on the type ofcaster used. It will be understood that other braking mechanisms may beconsidered herein without departing from the general scope and nature ofthe present disclosure. As noted, commercially available brakingmechanisms are available from Tente. Furthermore, different brakingmechanisms 292 may be used for different casters 202, depending on theintended purpose and use of such brake mechanisms.

In particular, the central levering mechanism 282 comprises a sleevemember 296 that is slid toward the center of shaft 288 and coupled tothe driven member 284 via flanges 297 extending radially outwardtherefrom. A bolt or pin 298 is further provided through the shaft 288and biased within a notch 300 formed in through a periphery of thesleeve 296 by a spring mechanism 302, thereby operatively coupling thesleeve 296 to the shaft 288 when the pin 298 is so biased, such that arotation of the sleeve 296 under a pivoting action applied to theflanges 296 by the driven member 284, induces a rotation of the shaft288. As will be described below, when the override pedal 290 isdeployed, the shaft 288 is shifted toward the right such that the pin298 is released from the notch 300, thereby uncoupling the shaft 288from the sleeve 296 and allowing for manual operation of the casterbrake mechanisms 292.

The shaft 288 extends across the base frame 200 and through to thelateral levering mechanisms 292 such that a rotation of the shaft 288imparts a substantially linear displacement of the bars 294. As recitedabove, displacement of the bars 294 generally translates into operationof each caster's brake mechanism 292 via respective brake actuatinglevers 295. A protective cover 299 may also be provided to hide andpossibly protect the bars 294 and other elements of the braking system206.

As introduced above, an override pedal 290 is provided on the right-handside of the bed 100 and is operatively coupled to the lateral leveringmechanism 286 on this side. In general, the override mechanism ispractical in situations where the actuator 280 is in a given positionand power thereto or to the control system 1000 is unavailable, thuspreventing the actuator 280 from changing from one mode to another. Inone embodiment, the pedal 290 is spring-biased in an upright and stowedposition (FIGS. 12 and 13) such that a downward pivoting force isrequired to extend the pedal 290 to an operable position in which anoperating surface thereof 304 is substantially parallel with the floor(FIGS. 14 to 16). Furthermore, the pedal 290 may be configured such thatwhen it is stowed, a clearance of about five inches is maintained belowthe pedal 290 irrespective of the pedal's orientation. Although thisclearance may be obstructed when the pedal 290 is engaged, the clearanceis regained automatically as the pedal 290 is returned to its stowedposition.

When such a force is applied to the pedal 290, a corresponding set ofpivoting flanges 308 are configured to pivot and engage a bolt 310transversally fastened through the end of the shaft 288 such that theshaft 288 is pulled toward the pedal side of the bed 100, therebyreleasing the pin 298 from notch 300 and disengaging the actuator 280from operative control of the braking system 206. As a result, controlof the braking system 206 is then provided via the deployed pedal 290rather than the motorized actuator 280 and controls thereof. When thefoot or hand of the operator releases the pedal 290, the latter springsback to its upright position and the pin 298 is again urged toward thenotch 300 by the spring mechanism 302.

In one embodiment, the release of pedal 290 is monitored by a switch 291configured to report to the control system 1000, whether the brakingsystem 206 is currently in override mode. For example, as shown in FIG.11, as the shaft 288 is pulled toward the pedal 290, a leveringmechanism 293 may be configured to release a user actuatable device,such as a switch 291, indicating that the braking system 206 is inoverride mode. When the pedal 290 is released to its upright position,the switch 291 is pressed and reports this event to the control system1000, which may then activate the actuator 280 to pivot the centrallevering mechanism 282 through its course thereby rotating the sleevemember 296 to realign the notch 300 therein with pin 298 so to re-couplethe actuator 280 with shaft 288. Alternatively, the pin 298 may bere-engaged with the notch 300 by manual rotation of the released pedal290, or again by a control user actuatable device, such as a button orswitch, provided therefor with the control system 1000.

In one embodiment, a visual indicator 312 is also provided above thepedal 290 and configured to indicate a status of the braking system 206as the breaking system 206, and consequently the pedal 290, is movedthrough different positions (e.g. brake, neutral, steer), eithermanually or automatically via control system 1000. A sensor 314, such asa user actuatable device, such as a button or switch or the like, mayalso be provided to report a brake status to the control system 1000,which may be conveyed to the operator via one or more visual userinterfaces, as described further below. In general, the brake statusindicator(s) may help to avoid having the user inadvertently leave thebed without the brakes being set, which could result in inconveniencesor safety concerns for the patient.

FIGS. 12A to 12C shows a change of the visual indicator 308 and a motionof the pedal 290, when stowed, as the braking system 206 is selectivelymoved from steer, neutral and brake positions respectively.

FIGS. 13A to 13C show an automatic actuation of the braking system 206in steer, neutral and brake positions respectively. For instance, inFIG. 13A, the actuator 280 fully extends the driven member 284 to pivotthe handle 290 toward the head-end of the bed 100, thereby moving thebars 294 toward the foot-end of the bed 100, which in turn positions thecaster breaking systems 292 in steer mode. In one embodiment, steer modeimplies that all casters 202 are free to rotate and pivot, for examplewhen a drive wheel mechanism is used. In another embodiment, steer modeimplies that only head-end casters are free to rotate and pivot, whilefoot-end casters are pivotally immobilized. In the latter case,selecting the steer mode may pivotally immobilize the foot-end castersin their current orientation until a push or pull force is applied tothe bed, at which point these casters will orient themselves with anaxis of the bed and lock to maintain this orientation as they rotate.

In FIG. 13B, the actuator 280 partially extends the driven member 284 tolevel the handle 290, thereby centering the bars 294, which in turnpositions the caster breaking systems 292 in neutral mode. In oneembodiment, neutral mode implies that all casters 202 are free to rotateand pivot.

In FIG. 13C, the actuator 280 fully retracts the driven member 284 topivot the handle 290 toward the foot-end of the bed 100, thereby movingthe bars 294 toward the head-end of the bed 100, which in turn positionsthe caster breaking systems 292 in brake mode which immobilizes thecasters 202. During operation when the bed 100 is not moving, userstypically engage the braking system 206. Users can visually verify thestatus of the brake position with the status indicator 308, depicted inFIG. 12.

FIGS. 14 to 16 illustrate the manual override of the braking system 206,wherein the pedal 290 is deployed, generally by the foot of a user,though hand operation may also be contemplated. In general, asintroduced above, when the pedal 290 is deployed, the pin 298 isreleased from notch 300 thereby uncoupling the actuator 280 and theshaft 288.

The pedal 290 can then be used to manually override the braking system206 using foot or hand actuation. In FIGS. 14A to 14C, the actuator 280coupling to the shaft 288 is released when in the steer position andremains in this position while the pedal 290 is moved from a brakeposition (FIG. 14A), through a neutral position (FIG. 14B), to a steerposition (FIG. 14C). In FIGS. 15A to 15C, the actuator 280 coupling tothe shaft 288 is released when in the neutral position and remains inthis position while the pedal 290 is moved from a brake position (FIG.15A), through a neutral position (FIG. 15B), to a steer position (FIG.15C). In FIGS. 16A to 16C, the actuator 280 coupling to the shaft 288 isreleased when in the brake position and remains in this position whilethe pedal 290 is moved from a brake position (FIG. 16A), through aneutral position (FIG. 16B), to a steer position (FIG. 16C).

As stated above, when the pedal 290 is released, the pin 298 is againurged toward the sleeve member 296 such that as the sleeve 296 isrotated about the shaft 288 by activation of the actuator 280, the pin298 eventually re-engages the notch 300 therein, thereby re-coupling theactuator 280 to the shaft 288 and caster braking mechanisms 292.Alternatively, the shaft 288 and pin 298 can be rotated manually usingthe stowed pedal 290 until the notch 300 is re-engaged by the pin 298.

The Elevation System

The bed 100 further comprises an elevation system 500 that allows thebed 100 to be raised or lowered relative to the floor. In certainembodiments of the invention, the elevation system 500 allows the bed100 to be raised and configured into various positions. For example, asintroduced above, the lift arms 502 and linear actuators 504 of theelevation system 500 may be configured to position the intermediateframe 400 of the bed 100, and ultimately the deck support 700 and lyingsurface 800 mounted thereon, in at least some of the followingpositions: a raised or upper substantially horizontal position whereinintermediate frame 400 is at least partially raised above the base frame200 (e.g. see FIGS. 1 to 8, 17A, 18A and 20A); a Trendelenburg positionwherein a head-end 402 of intermediate frame 400 is lower than afoot-end 404 thereof (e.g. see FIGS. 17B and 18B); a ReverseTrendelenburg position wherein the foot-end 404 of intermediate frame400 is lower than the head-end 402 thereof (e.g see FIGS. 17C, 20B and20C, wherein the bed 100 in FIG. 20C is in a lowered ReverseTrendelendburg position); and a lowered substantially horizontalposition wherein the intermediate frame 400 is lowered adjacent to thebase frame 200 (e.g. see FIGS. 17D and 18C). Furthermore, the elevationsystem 500 enables raising and lowering of the bed 100 without anysubstantial longitudinal (or lateral) movement of the intermediate frame400, and ultimately of the deck support 700 and lying surface 800mounted thereon. As well, the elevation system can be driven by a motor,as illustrated herein, or be otherwise power-assisted, therebyminimizing the physical effort required to raise and lower the height ofthe bed 100. As will be described below, the elevation system 500enables raising and lowering of the bed 100 without any substantiallongitudinal (or lateral) movement of the intermediate frame 400, andultimately of the deck support 700 and lying surface 800 mountedthereon. For example, the elevation system 500 enables raising andlowering of the bed 100 so that the support frame system remainssubstantially bounded between two parallel planes when raised or lowerand further so that the maximum deviation along the longitudinal axis ofthe bed is less than 1 inch, more optimally less than 3/4 inch, and moreoptimally less than ½ inch.

With reference to FIGS. 17 to 23, and particularly to FIGS. 21 and 23,an illustrative configuration of the lift arms 502, in accordance withone embodiment of the elevation system 500 of the present invention,will now be described in greater detail. In this embodiment, the liftarms 502 are attached between the base frame 200 and the intermediateframe 400. In particular, the lift arms 502 may comprise a pair ofhead-end lift arms 506 operatively coupled toward the head-end 102 ofthe bed 100, and a pair of foot-end lift arms 508 operatively coupledtoward the foot-end 104 of the bed 100. Furthermore, each lift armwithin pairs 506 and 508 comprises a pair of cooperating primary andsecondary lower arm members 510 and 512, and an upper arm member 514,the combination of which being actuated by a linear actuator 504respective to each pair 506 and 508.

FIGS. 22A, 22B and 23 provide exploded views of an assembly of thehead-end lift arms 506 (FIGS. 22A and 23) and foot-end lift arms 508(FIG. 22B). As stated above, each lift arm 502 comprises a pair ofcooperating primary and secondary lower arm members 510 and 512, and anupper arm member 514. In general, the lower arm members 510, 512 arecoupled to the base frame via a coupling bracket 516 fixedly attached tothe side rails 210, 212 of the base frame 200. In particular, theprimary lower arm member 510 is fixedly coupled to an actuation shaft518 that is rotatably coupled in a conventional manner (e.g. via abushing assembly 519 or the like) within a cylindrical cavity 521 ofbracket 516. A pair of levering flanges 524, fixedly disposed on theshaft 518, are used to couple the shaft 518 to one of the linearactuators 504 thereby configured to impart a rotation to the shaft 518and to the primary lower arm member 510 thereabout. The secondary lowerarm member 512 is also rotatably coupled in a conventional matter withina second cylindrical cavity 523 of bracket 516, and is generally notdirectly affected by a rotation of the shaft 518.

The upper arm member 514 is pivotally coupled at its upper end to theintermediate frame 400 via a coupling bracket 520 (or brackets 522 forfoot-end pairs 508) and at its lower end to the lower arm members 510,512. Note that the coupling bracket 520 for head-end arms 506 comprisesa linear slot 526 to accommodate a relative longitudinal displacement ofthe upper ends of upper arm members 514 of the head-end and foot-endpairs 506 and 508 respectively, whereas the coupling brackets 522 forfoot-end arms 508 comprise a single pivot point 528. This linear slot526 is generally provided to accommodate such longitudinal displacementswhen the head-end or foot-end of the bed 100 is lowered relative to theother, for instance to achieve a Trendelenburg or reverse Trendelenburgposition. The person skilled in the art will understand that a similarelevation system 500 could provide a linear slot at the foot-end of thebed 100, or again a combination of slots depending on the selected liftarm geometry.

The coupling of the upper arm member 514 to the lower arm members 510,512 is provided via two distinct pivot points 530 and 532, respectively.Based on this geometry, as the primary lower arm member 510 pivots withshaft 518, the pivot point 530 is urged to revolve with the shaft 518 inits direction of rotation. Simultaneously, the secondary lower armmember 512 will impart a counteracting force upon pivot point 532thereby urging the upper arm member 514 to pivot about pivot point 530in a rotational direction opposite to that of the primary arm member510.

For example, with reference to FIGS. 21, 22A and 23, when the head-endarm pair 506 is in a lowered position, the actuator 504 associatedtherewith may be activated to impart a counterclockwise rotation to theshaft 518, which imparts a counterclockwise rotation of the primarylower arm members 510, and consequently a counterclockwise revolution ofthe pivot points 530, about this shaft. Simultaneously, the secondarylower arm members 512 will urge, via pivot point 532, the upper armmembers 514 to pivot about pivot point 530 in a clockwise direction,thereby raising the head-end 102 of the bed 100. As will be readilyunderstood by the person skilled in the art, reverse operation of theactuator 504 will reverse the above process to lower the head-end 102 ofthe bed 100. It will also be understood that the foot-end lifting armpair 508 may be operated in a similar fashion.

In one embodiment, the pivot points 530 between primary lower armmembers 510 and upper arm members 514 of the foot-end lift arms 508 areupwardly biased by a torsion spring 533 disposed about these pivotpoints 530, a first leg of which being secured beneath outwardlyextending pivot pins 535, and a second leg of which being secured aboveinwardly extending flanges 537. This spring-loaded embodiment may beuseful, for example, to assist the lift mechanism 500 when most of thepatient's weight is on the foot-end of the bed 100, for example in aseated or head-elevated position. Further, torsion spring 533 may reducethe load on the actuator and alleviate power to the actuator. Typically,the greatest forces on the actuator occur when the patient support is atits lower-most position relative to the base. Therefore, spring 533reduces the load on the actuator for at least a portion of the range ofmotion of the actuator (or the patient support relative to the base).For example, the spring 533 may reduce the force for at least the 50% ofthe range of motion for the actuator (or for patient support). It willbe appreciated that a similar spring-assisted system may be contemplatedfor the head-end lift arms 506 if needed, without departing from thegeneral scope and nature of the present disclosure.

With reference to FIGS. 24A, 24B and 25A to 25D, in one embodiment, toachieve a substantially vertical elevation with minimal longitudinaldeviation of the intermediate frame 400 relative to the base frame 200,the primary and secondary lower arm members 510, 512 are disposed todefine an angle between them. By proper selection of the length anddisposition of the lower arm members 510, 512, as well as the angledefined between them, a longitudinal deviation of the intermediate frame400 relative to the base frame 200 as the elevation system 500 extendsand retracts can be minimized. For example, a maximum deviation of 1inch or less, more optimally of ¾ inch or less, and even more optimallyof less than ½ inch.

As illustrated in FIGS. 22A and 22B, the upper and/or lower arm membersof a given pair may be interconnected by a reinforcing member 534 tosolidify and maintain a distance between such arm members. Also, asillustrated in FIGS. 21 and 23, lifting arm covers 536 may be providedto cover the lifting arm mechanism described above and thereby providean aesthetic finish to the bed's elevation system 500. For example, theupper arm members 514 may be covered by a common cover that is formed bytwo cover halves 536 a that when coupled together span across the upperarm members 514. Each of the pairs of lower arm members 510, 512similarly may include a cover formed from two cover halves 536 b, 536 c.As best seen in FIG. 23, these covers have a split-housing construction,which are then fastened together about the respective arm componentswith a snap-fit or other similar connections. Covers 536 may be formed,such as by molding, including molding from plastic or from aluminum ormagnesium or other moldable materials. Covers 536 may also be cast from,for example aluminum.

In FIG. 24A, the geometrical axes of the actuator 504, the primary andsecondary lower arm members 510, 512, and the upper arm member 514 areshown for various elevations of the intermediate frame 400, the axescorresponding to the depicted components of the elevation mechanism 500at a next to lowermost position being shown in bold. In FIG. 24B, thesame axes are shown without illustration of the mechanism's components,reference numerals generally associated with these components beingassociated with their respective corresponding axes instead. As can beseen in these Figures, the respective axes of the primary and secondarylower arm members 510, 512 are angled relative to one another, whichallows for the longitudinal travel of the intermediate frame 400 as itraises and lowers, illustrated by the displacement of the couplingbracket 522, to be minimized. For instance, the amplitude of thesinusoidal path or curve traced by the bracket 522 as it moves up anddown under action by the lift arm 502 is kept relatively small. Forexample, the maximum amplitude of less than 1 inch, more optimally lessthan ¾ inch, and more optimally less than ½ inch. By adjusting the anglebetween the primary and secondary arm members 510, 512, this result maybe improved to a desired setting.

FIGS. 25A to 25D show a displacement of the aforethe axes from alowermost position (FIG. 25A) to an uppermost position (FIG. 25D). Usingthis design, the bed 100 may be raised and lowered by the elevationsystem 500 with minimal longitudinal displacement. As will be readilyapparent to the person of skill in the art, the characteristicsdescribed with reference to FIGS. 24A, 24B and 25A to 25D wherein thefoot-end lift arms 508 are depicted, may apply equally to the head-endlift arms 506. As such, by minimizing a longitudinal travel of theintermediate frame 400 under action from both the head-end and foot-endlift arms 506, 508, an overall longitudinal travel of the intermediateframe when raised or lowered is minimized.

In accordance with one embodiment of the invention, the liftingmechanism 500 is governed by the control system 1000 introduced aboveand described in further detail below. For instance, actuation ofactuators 504 may be controlled by one or more user actuatable devices,such as push buttons or interactive displays on one or more controlpanels 1004 such that a positioning and orientation of the bed'sintermediate frame 400 (and deck support 700 and lying surface 800mounted thereon) relative to the base frame 200 is governedelectronically. These and other such considerations will be discussedfurther herein below.

The Intermediate Frame

Some aspects of the versatility and adjustability of the bed 100, inaccordance with different embodiments of the present invention, areachieved by providing an intermediate frame 400 that is designed toallow a variety of adjustments to the foot-end of the bed 100,particularly of the foot sections 706 and 806 of the deck support 700and lying surface 800 respectively. In one embodiment, the intermediateframe 400 allows the bed 100 to be configured into positions where apatient's legs are lower than the rest of the body (e.g. see FIG. 4),such as in a partially or fully seated chair configuration (e.g. seeFIGS. 5 to 7). For instance, by providing an intermediate frame 400whose length is at least partially reduced relative to the full lengthof the bed 100, actuation of the foot section 706 of the deck support700 pivotally connected thereabove may be facilitated in a downwarddirection as a structural obstruction commonly produced by a full lengthintermediate frame is reduced and/or avoided completely. For example,the length of the intermediate frame 400 is less than the deck support700 and optimally terminates at or near the pivot point of foot-endsection 706 of deck support 700.

Such an intermediate frame 400 is useful in situations such as hospitalenvironments, where it can alleviate the need to transfer patients froma bed to a chair and back for procedures which require uprightpositioning, or for allowing patients to sit up more comfortably forsocial or other personal purposes without requiring a chair transfer. Inaddition, certain medical positions require the patient to have his orher legs placed lower than the rest of the body. The intermediate frame400 allows the patient to alternate positions from a chair-typeconfiguration to the flat position, or any intermediary positiontherebetween.

In one embodiment, the foot-end of the bed is designed to allow the footsection 706 of the deck support 700 to be lowered below the level of thehead and seat sections 702, 704 (e.g. see FIG. 4). This is accomplishedby means of a shortened intermediate frame 400 as noted above, uponwhich is mounted a load-bearing frame 600 and deck support 700, the footsection 706 of which being cantilevered or otherwise supported beyondthe end of the intermediate frame 400. As depicted for example in FIGS.34, 37 and 38, the foot section 706 projects or extends past theintermediate frame 400 so that it can be lowered without coming intocontact with the intermediate frame 400.

An exemplary embodiment of the intermediate frame 400 is shown in FIG.26. The intermediate frame 400 generally comprises opposing andsubstantially parallel longitudinal side rails 406, 408, (upon which arefixedly mounted the load cells 602, described further below), a head-endstructure 450 disposed at a head-end 402 thereof, and a foot-endstructure 410 disposed at a foot-end 404 thereof.

The Foot-end Structure

In general, the foot-end structure 410 comprises a substantiallyU-shaped structure that is fixedly attached below the side rails 406,408 via longitudinally extending members 412 thereof. In one embodiment,the intermediate frame 400 may include one or more attachment means formounting devices to the bed. In the illustrated embodiment, the members412 of intermediate frame 400 may include the attachment means, such assupport brackets 414, for fixedly or removably attaching variousequipment, accessories and/or devices to the bed 100. Each supportbracket 414 may be formed from a plate bracket 414 a with a plurality ofelongate openings 414 b for receiving hooks, cables or the like forhanging or mounting the devices from the bed. Plate brackets 414 a maybe mounted to the frame, for example, by fasteners 414 c; though itshould be understood that they may also be welded or riveted or securedin place by other means.

Using these attachment means 414, which are coupled to the bed framebelow the load cells 602, the weight of the attached objects will notinfluence the load readings acquired via the load cells 602. As such,adding and removing objects from these attachment means 414 does notrequire that the weight of these objects be taken into account by theload measuring and/or monitoring system, either manually, or via arecalibration of the system.

The foot-end structure 410 further comprises, in this embodiment, thefoot-end coupling brackets 522 described above and provided to pivotallycouple the upper arm members 514 of the foot-end lift arms 508 to theintermediate frame 400 in order to controllably lift and lower thefoot-end 404 of the intermediate frame 400 relative to the base frame200, as described above, for example, with reference to FIGS. 17A to17D, etc.

The Head-end Structure

The head-end structure 450 is generally fixedly mounted to the siderails 406, 408, further supported by support plates 418 integrallycoupled thereto. In general, the head-end structure 450 provides for theoperative coupling of the push handles 451 to the bed 100, which may beused to control the optional drive wheel mechanism described above. Thehead-end structure 450 may further comprise one or more control panelsand/or interfaces, as in interfaces 453, 455, and/or plug-ins, as innetwork plug-ins 457, input power plug-ins 459, or the like, forcontrolling, monitoring and/or operating the bed 100 and a patient lyingthereon. For example, as illustrated in FIG. 57, a control interface 994is shown for interface 453 providing a medical practitioner control ofthe bed's orientation and configuration, which are also illustrativelyprovided by the head-end side rail panel 993 (discussed further below).

The head-end structure 450 may further comprise a number of structuralcomponents, such as for example, a pair of headboard sockets 452 forreceiving therein headboard mounting post 968 for mounting the headboard906 thereto, or other such sockets 454 for supporting therein variousequipment, devices and/or accessories. As with the support brackets 414of the foot-end structure 410, the sockets 454 allow for objects to becoupled thereto without a weight thereof affecting the load measurementsacquired via the load cells 602. The head-end bracket 450 furthercomprises the head-end coupling brackets 520, comprising linear slot526, described above and provided to couple the upper arm members 514 ofthe head-end lift arms 506 to the intermediate frame 400.

In FIGS. 27 to 29, a head-end structure 450, in accordance with anillustrative embodiment of the present invention, is depicted in greaterdetail. The head-end structure 450, is generally comprised of a lowermodule 456, comprising the coupling brackets 520 and configured forfixing to the side rails 406, 408, and an upper module 458 mounted atopthereof.

In general, the push handles 451 (FIG. 30) are operatively coupled tothe lower module 456 via a levering support structure 460 pivotallycoupled to load cell 462 (FIG. 27) which is fixedly attached to thebottom surface of the lower module 456. The handles 451 are themselvespivotally coupled to the support structure 460 and movable between araised or deployed operative position (e.g. right handle of FIG. 3), anda lowered or retracted inoperative position (e.g. left handle of FIG.3). For example, when not being used to displace the bed, one or bothpush handles 451 may be placed in a stored position such as by removingthem from the bed or by folding them inwards, as depicted in FIG. 3.Typically it is convenient to access or remove the headboard when thepush handles are stored.

A user actuatable device 464, such as an activation button, is furtherprovided on the handles 451 such that even when a handle 451 isdeployed, it remains inoperative until the button 464 is activated. Inoperation, when the support structure 460 is pivoted by a pressureapplied to one of the handles 451, the load cell 462 registers andcommunicates the applied pressure to the control system 1000, which maythen translate this pressure into an operational drive command to theoptional drive system described above with reference to FIG. 9. In oneembodiment, the drive command may be graduated as a function of thepressure intensity applied to the handle(s) 451.

As will be described in greater detail below, activation of the drivemechanism using the push handles 451 may be conditional on a prioractivation of the drive mechanism. For example, as introduced above,selection of the drive or steer mode on one of the beds control panels,for instance via interface panel 453, may be needed for example, torelease brakes previously applied, to lower the drive wheel in operativecontact with the floor, and/or address a number of other possiblerestriction requirements associated with the patient resting on the bedin question. These and other such characteristics of the drive mechanismand push handle activation thereof will be described in greater detailbelow.

The Load Frame

The load frame 600 is generally provided to rest atop, and beoperatively coupled to, the load cells 602 disposed on the intermediateframe 400, and configured to support the deck support 700 and lyingsurface 800 thereabove. As a result, any addition of weight, or anyshift of weight applied to bed 100 from above the load frame 600, thatis directly or indirectly to the lying surface 800 or deck support 700,can be monitored via the load cells 602. Figuratively, the load frame600 vertically divides the bed 100 into a lower section below the loadframe 600 comprising the intermediate frame 400, the elevation system500, the base frame 200 and their respective components, and an uppersection above the load frame 600 comprising the deck support 700 andlying surface 800 upon which a weight variation may be detected and/ormonitored via the load cells 602.

FIG. 31 depicts an exemplary embodiment of the load frame 600. Ingeneral, the load frame 600 comprises two opposed substantially parallellongitudinal side rails 604, and a head-end cross bar 606 andintermediate and foot-end rails 608 and 610, respectively, eachstructurally coupled between the side rails 604. The side rails 604comprise a substantially inverted U-shaped cross section sized to fitover the intermediate frame side rails 406, 408, and comprise fourcoupling holes 612 disposed and configured to be coupled tocorresponding load cell apertures via coupling pins 614 such that anyweight applied to the load frame 600 is communicated to the load cells602 through these pins 614.

The intermediate and foot-end rails 608, 610, generally provide, as doesthe side rails 606 in some instances, a number of coupling brackets forpivotally connecting the various components of the deck support 700 tothe load frame 600, as well as provide couplings for the variousactuators and/or levers used to move these components relative to theload frame 600. In general, in order for all weight changes applied tothe deck support 700 and lying surface 800 to be sensed and optionallymonitored by via the load cells 602, the deck support 700 should, inmost cased, be substantially isolated from the any component of thebed's framing operatively located below the load cells 602. That, aswill be apparent to the person skilled in the art, the deck supportcomponents should be coupled to the bed such that substantially none ofthe weight of these components, or of any object or person restingthereon, be transferred to the intermediate frame 400, elevation system500, or base frame 200 other than via the load frame's interconnectionto the load cells 602. For reasons of clarity, the various couplingbrackets provided by the load frame 600 for mounting the variouscomponents of the deck support 700 thereto will be described in thefollowing section dealing specifically with the deck support 700.

In one embodiment, the side rails 604 further comprise laterallyextending support members 615 for securing the foot-end side rails 904thereto (e.g. see FIG. 44). By coupling the foot-end side rails 904 tothe load frame 600 rather than to a movable component of the decksupport 700, as is the case for the head-end side rails 902, thefoot-end side rails 904 will not move with the deck support 700 but willrather maintain their orientation independently of the deck support'sorientation. The person of skill in the art will understand that inother embodiments, the foot-end side rails 904 could also be coupled tothe deck support 700, for instance to the seat section 704 thereof whichdoes not traditionally comprise a wide angular range.

In one embodiment, the load frame 600 further comprises a pair of guidechannels 616 (FIG. 31) for guiding wires, cables, or other conduits,including tubing for delivering fluid, such as air. Each guide channels616 includes a first substantially J-shaped rail 618 fixedly mounted toa side rail 606, and a staggered rail 620 having an upwardly extendingflanges for coupling this rail 620 to the side rail 606 through theJ-shaped rail 618. The outwardly and downwardly extending flanges of thestaggered rail 620 are so formed as to cooperatively define with thebottom section of the J-shaped rail 618 the guide channels 616. Asnoted, these guide channels 616 can be used to guide a number of wires,cables and or other such conduits therethrough without impeding with theload-bearing functionality of the load frame 600. As noted, theseconduits may be used to channel tubing through the bed for supplyingfluid, such as air, to the various components on the bed. For example,should an air bearing pallet be needed to transfer a patient from bed100 to another patient support device, the tubing may be used to inflatethe pallet.

Furthermore, in one embodiment, the load frame 600 comprises a sensor622 (mounted to one of the side rails 606 in the embodiment of FIG. 31),such as an inclinometer or the like, to detect variations in theinclination/orientation of the load frame 600. As will be described ingreater detail below, data acquired using this and other such sensorsdisposed on various parts of the bed can be used in calculating andmonitoring various characteristics of the bed 100 and/or of a patientlying thereon. As will be apparent to the person skilled in the art, thesensor can be mounted elsewhere on the head section 702 withoutdeparting from the general scope and nature of the present disclosure.

The Deck Support

Referring to FIGS. 32, 33, and 34, the deck support 700 is generallycomprised of a head section 702, a seat section 704 and a foot section706. As presented above, the various sections of the deck support 700and lying surface 800 may be moved relative to the intermediate and/orload-bearing frames 400, 600 to move a user on the bed to variouspositions. For example, it may be required to configure the lyingsurface 800 of the bed 100 in a configuration that is designed to assista caregiver in providing CPR to the patient supported thereon. In oneexample, a CPR configuration is defined by placing the head, seat andfoot sections 702, 704 and 706 of the deck support 700 in a generallylinear relationship (e.g. see FIG. 32). In one embodiment, the bed canbe placed in this pre-defined CPR configuration via the control system1000, which can comprise one or more control panels configured tocontrol a number of linear actuators operatively disposed to actuate thevarious sections of the deck support 700 (e.g. see FIG. 57).

Other positions may also be considered useful in providing care to apatient positioned on the bed 100. For instance, with reference to FIG.8, the head section, seat section and foot sections 702, 704 and 706 maybe positioned in a substantially linear relationship to provide asubstantially flat lying surface 800. In one embodiment, the headsection 702, seat section 704 and foot section 706 are placed in thislinear relationship by the control system 1000 in response to a singleuser actuatable device, such as a button, being depressed on one of thecontrol system's various control panels (described below).

With reference to FIGS. 5 to 7 and 33 to 35, the head section 702 can berotated about pivot 708, such that a head-end 710 of the head section702 is raised relative to a foot-end 712 thereof. For example, thehead-end 710 may be raised by the control system 1000 controlling anactuator 714 (FIGS. 34 and 35) to further extend a cylinder 716 of thisactuator 714 and thereby raise the head-end 710. In one embodiment, thehead section 702 is raised by the control system 1000 in response to afirst user actuatable device, such as a button, being depressed on oneof the control system's various control panels (e.g. see FIG. 57), andlowered by the control 1000 system in response to a second useractuatable device, such as a second button, being depressed on this samepanel or another panel.

Furthermore, with reference to FIGS. 4 to 7, 33 and 36, the seat section704 can be similarly rotated about pivot 718 such that its foot-end 720is raised relative to its head-end 722. The seat section's foot-end 720may be raised by the control system 1000 controlling an actuator 724(FIG. 33) to further extend a cylinder 726 of the actuator 724 therebyraising the seat section's foot-end 720. In one embodiment, the seatsection 704 is raised by the control system 1000 in response to a firstuser actuatable device, such as a button, being depressed on one of thecontrol system's various control panels (e.g. see FIG. 57), and loweredby the control 1000 system in response to a second user actuatabledevice, such as a button, being depressed on this same panel.

Also, with reference to FIGS. 4 to 7 and 34, the foot section 706 can besimilarly rotated about pivot 728 such that its foot-end 730 is loweredrelative to its head-end 732. The foot section's foot-end 730 may belowered by the control system 1000 controlling an actuator 734 toretract a cylinder 736 of the actuator 734 (FIG. 34) thereby loweringthe foot section's foot-end 730. In one embodiment, the foot section 706is lowered by the control system 1000 in response to a first useractuatable device, such as a button, being depressed on one of thecontrol system's various control panels (e.g. see FIG. 57), and loweredby the control 1000 system in response to a second user actuatabledevice, such as a button, being depressed on this same panel.

The Head Section

With reference to FIGS. 32 to 35, in accordance with an illustrativeembodiment of the present invention, the head section 702 generallycomprises a framework 738 on which is mounted a pair of side plates 740configured to receive thereon, in one embodiment, a cover plate 742translucent and substantially transparent to X-rays and/or otherfluoroscopic beams conventionally used to evaluate a patient'scondition. The use of such a cover plate 742 may be practical, forinstance, when a patient cannot or should not be moved from the bed. Insuch a situation, fluoroscopic and/or radiometric tests on the patient'shead and torso may still conducted through the bed's head section 702.Alternatively, if such a feature is not required or desired, a singlecover plate may be used instead. Two or more mattress restraints 744 mayalso be provided to help restrain movement of the lying surface headsection 802 on the deck support's head section 702, and optionally, toprovide attachment points for patient restraints or the like.

The head section 702 is illustratively mounted to the load frame 600 viapivots 708, generally defined in this embodiment by the sliding andpivoting engagement of pins or protrusions 746 with slotted brackets748. A set of guide arms 750 are also provided to guide a motion of thehead section 702 as it pivots and slides within slotted brackets 748 toaccommodate for the corresponding movement of the lying surface 800disposed on the deck support 700. Referring to FIG. 34, the actuator714, pivotally coupled to coupling bracket 752 of the load frame'sfoot-end rail 610, is operatively coupled to lever 754 configured toimpart a pivoting action to the head section 702 about pivot 708 whilethe foot-end thereof 712 slides toward the head-end of the bed underaction of the actuator 714.

In one embodiment, the head section further comprises an emergencyhandle 756 (e.g. see FIG. 35) configured to disengage the actuator 714in the event of a power failure or an emergency when the head section702 must be lowered rapidly, for example to administer CPR to a patient.For example, handle 756 includes a cable 756 a that connects to a collaron the actuator, which is coupled to a clutch on the actuator and whenpulled decouples the driving force of the actuator from lever 754. Wheretwo handles are provided, the respective cables 756 a of the handles 756are directed to a junction box 756 b where the two cables couple to asingle cable that is then coupled to the collar on the actuator so thatif either handle is pulled the actuator will be decoupled from thelever.

Furthermore, in one embodiment, the head section 702 comprises a sensor758 such as an inclinometer of the like (mounted to lever 754 in theembodiment of FIG. 33), to detect variations in theinclination/orientation of the head section 702. As will be described ingreater detail below, data acquired using this and other such sensorsdisposed on various parts of the bed can be used in calculating andmonitoring various characteristics of the bed 100 and/or of a patientlying thereon. As will be apparent to the person skilled in the art, thesensor can be mounted elsewhere on the head section 702 withoutdeparting from the general scope and nature of the present disclosure.

As will be more full described below in Reference to FIG. 45A,optionally, to provide a quick reference to the angular or inclinedposition of the head-end section, bed 100 may be provided with one ormore visual indicators 905 on foot-end side rail 904.

The Seat Section

With reference to FIGS. 32, 33 and 36, in accordance with anillustrative embodiment of the present invention, the seat section 704generally comprises a framework 760 on which is mounted a cover 762 toreceive the lying surface 800 thereon. The seat section 704 isillustratively mounted to the load frame 600 via pivots 718, generallydefined in this embodiment by the pivoting engagement of pins 764 withbrackets 766. The actuator 724, pivotally coupled to coupling bracket768 of the load frame's intermediate rail 608, is operatively coupled tolever assembly 770 configured to impart a pivoting action to the seatsection 704 about pivot 718 under action of the actuator 724.

Furthermore, in one embodiment, the seat section 704 comprises a sensor772 such as an inclinometer of the like (mounted to the framework 760 inthe embodiment of FIG. 33), to detect variations in theinclination/orientation of the seat section 704. As will be described ingreater detail below, data acquired using this and other such sensorsdisposed on various parts of the bed can be used in calculating andmonitoring various characteristics of the bed 100 and/or of a patientlying thereon. As will be apparent to the person skilled in the art, thesensor can be mounted elsewhere on the seat section 704 withoutdeparting from the general scope and nature of the present disclosure.

The Foot Section

With reference to FIGS. 32, 34 and 37 to 39, in accordance with anillustrative embodiment of the present invention, the foot section 706generally comprises a housing 774 on which is mounted a cover 776 toreceive the lying surface 800 thereon. The housing 774 is generallyconfigured to house therein a number of the power and control componentsof the bed 100. For example, in the illustrative embodiment of FIG. 38,the housing 774 encloses two batteries 778, a toroid 779 for convertinginput and output voltages as needed to operate the various electricalcomponents of the bed 100 (e.g. 12/24V/120/240V/etc.), a mother board780 and associated hardware and other such components as will be readilyunderstood by the person skilled in the art.

As illustrated in FIG. 37, power may be drawn from plug-in 459 andrelayed to the foot section 706. Consequently, the foot section 706 mayfurther comprise one or more optional power outlets 782 allowing variousperipheral devices and/or equipment to be powered through the bed'sinternal wiring. Backup battery power may also be available. Powerand/or control signals may also be communicated to various parts of thebed 100. For example, as shown in FIG. 39, a cable for communicatingwith an actuated lying surface 800 is provided to control this lyingsurface 800.

In this embodiment, the housing 774 further comprises a foot-endstructure 783 configured to support, amongst others, the footboard 908of the bed 100. In particular, a pair of footboard posts 972 may befitted in coupling sockets 784 to support the footboard 908 thereat.Power and communicative links to the footboard 908, for example to powerand communicate with the footboard's control console 976 and/ornetwork/external plug-ins 982, may be provide by connector 794configured to cooperate with a plug-in 984 of the footboard 908 (e.g.see FIG. 53).

The foot-end structure 783 may also comprise additional sockets 785provided to support various accessories/equipment for use with the bed100 or to treat or monitor the patient. In one embodiment, a switch (notshown) may be provided within one or more of these sockets 785 such thatwhen a socket 785 is in use, the foot section 706 cannot be lowered.This may be useful when the lowering of the foot section 706 equipmentwith a given accessory would create an undesirable obstacle to medicalpractitioners attending to the patient.

The housing 774 may further comprise a support, such as a support rack786 (FIG. 39), also configured to support various accessories/equipmentused, for example, for treating or monitoring a patient. In theillustrated embodiment, the support rack includes a plurality ofdiscrete holding locations for supporting a plurality of devices fromthe bed. As best seen in FIG. 37, support rack 786 is formed form aplate bracket 786 a that includes an elongate opening 786 b. Formed atthe edge of the opening 786 b are plurality of spaced notches 786 thatform the plurality of discrete holding locations for devices to be hungfrom the bed, for example, pumps, bags or the like. Plate brackets 786 amay be mounted to the frame, for example, by fasteners, though it shouldbe understood that they may also be welded or riveted or secured inplace by other means.

Note that as these accessories/equipment hang from a point operativelyabove the load cells 602, variation in the weight of theseequipment/accessories should be accounted for when interpreting loaddata.

As for the head section 702, two or more mattress restraints 788 mayalso be provided on the foot section 706 to help restrain movement ofthe lying surface foot section 806 on the deck support's foot section706, and optionally, to provide attachment points for patient restraintsor the like.

The foot section 706 is illustratively connected to the seat section 704via pivots 728 (FIG. 34), generally defined in this embodiment by thepivoting engagement of pins 781 within brackets 790 (foot section 706)and brackets 791 (e.g. see seat section 704 of FIGS. 33 and 36). Theactuator 734, pivotally coupled to coupling bracket 792 of the loadframe's foot-end rail 610 (e.g. as seen in FIG. 35), is operativelycoupled to a bracket (not shown) disposed under the housing 774 toward afoot-end thereof. As such, when the cylinder 736 is retracted, thefoot-end of the foot section 706 is pulled down toward the floor, andvice versa. Note that despite the interconnection of the foot section706 to the seat section 704, the motion of one does not significantlyaffect the position of the other. In fact, as the seat section is raised704, the foot section 706 may remain substantially horizontal. The sameapplies to the seat section 704 as the foot section 706 is lowered.

Furthermore, in one embodiment, the foot section 706 comprises a sensor(not shown) such as an inclinometer of the like to detect variations inthe inclination/orientation of the foot section 706. As will bedescribed in greater detail below, data acquired using this and othersuch sensors disposed on various parts of the bed can be used incalculating and monitoring various characteristics of the bed 100 and/orof a patient lying thereon. As will be apparent to the person skilled inthe art, the sensor can be mounted elsewhere on the seat section 706without departing from the general scope and nature of the presentdisclosure.

The Lying Surface

Referring to FIG. 7, a patient is supported on a lying surface 800,which can also be referred to as a mattress, a support surface, a lyingsurface, a patient surface, etc. For the purpose of this invention,these terms are used interchangeably to indicate the article upon whichthe patient lies, which is generally cushioned for patient comfort. Thearticle may be cushioned with foam, air, springs, or any othercushioning means known in the art. For example, suitable mattressesinclude Gaymar mattresses or foam mattresses. In one embodiment of thisinvention, the lying surface 800 is a mattress, such as found in ahospital setting. For ease of discussion, the term mattress is usedthroughout, although another type of article deforming a lying surface800 may be used.

As described above, the bed 100 of the present invention is capable ofbeing configured into a variety of positions so as to accommodate thepatient. For example, the sections of the deck support 700, i.e., thehead section 702, seat section 704, and foot section 706, can beadjusted to be raised or lowered into various positions. Consequently,the lying surface 800 also comprises a head section 802, a seat section804, and a foot section 806, all three being articulated relative to theother to move and follow the contour defined by the deck support 700.

The person of skill in the art will readily understand that variousstatic and/or adjustable lying surfaces 800 may be considered in thepresent context without departing from the general scope and nature ofthe present disclosure. For instance, adjustable mattresses comprisingpneumatically activated compartments configured to provide an adaptablesurface profile may be used for patients having reduced mobility and/orfor patients generally difficult to move. These and other suchmattresses may used with bed 100, the deck support 700 optionallyproviding power and/or control access to this type of lying surface 800via integrated control and/or auxiliary power sources.

The Barrier System

The bed 100 generally further comprises a barrier system 900 comprisedof structural barriers for ensuring the safety of a patient lying on thebed 100. Embodiments of the barrier system 900 may include anycombination of a headboard 906, a footboard 908, a pair of head-end siderails 902, and a pair of foot-end side rails 904.

FIGS. 40A to 54 show an embodiment of the barrier system 900,illustrating therein the various components of this barrier system 900in various positions. For example, FIGS. 40A and 40B show the fullbarrier system 900 when mounted adjacent the lying surface 800, whereinthe side rails 902, 904 are shown in their fully deployed or extendedposition in FIG. 40A, and in their fully retracted position in FIG. 40B.FIGS. 41 to 43 show an assembly of the head-end side rails 902 and theirattachment to the head section 702 of the deck support 700, whereasFIGS. 44 to 46 show an assembly of the foot-end side rails 904 and theirattachment to the load frame 600.

In FIGS. 47A to 47D and 48A to 48D, an exemplary foot-end side rail 904is shown in different positions, illustrating therein a dampingmechanism applied to this side rail 904 as it moves from one position toanother. In addition, FIGS. 49 and 50 show in greater detail ofillustrative embodiments of a guiding mechanism 954 and a lockingmechanism 928 (FIG. 45) for respectively guiding and locking a motion ofthe side rails 902, 904. FIGS. 51 to 54 provide various views of thefootboard 908 and of an optional control console 976 pivotally attachedthereto.

As will be understood by the person skilled in the art, theconstruction, configuration and operational mechanisms of the head-endand foot-end side rails 902, 904 are very similar in both design andoperation. As such, sections discussing the actuation, damping andlocking mechanisms of the side rails 902, 904, as well as variousgeneral discussions as to the fabrication and assembly of these siderails 902, 904, are cast with reference to various illustrations of anexemplary foot-end side rail 904. It will be appreciated that althoughreferencing only one illustrative embodiment of the bed's foot-end siderails 904, the following description applies equally, unless otherwiseindicated, to both the head-end side rails 902 and the foot-end siderails 904.

Side Rails

Referring now to FIGS. 40 to 50, an illustrative embodiment of the bed'sside rails 902, 904 will now be described. In general, head and foot-endside rails 902, 904 are configured to move between raised or deployedpositions, as shown for example in FIG. 40A and lowered or stowedpositions, as shown for example in FIG. 40B to permit entry and egressof patients into and out of the bed 100. Head-end side rails 902 areillustratively coupled to the head section 702 of the deck support 700(e.g. see FIG. 41) and may be moved between raised and loweredpositions. Foot-end side rails 904 are illustratively coupled to theload frame 600 (e.g. see FIG. 44) and may also be moved between raisedand lowered positions. As the head section 702 of the deck support 700rotates relative to the load frame 600, head-end side rails 902 alsorotate relative to the load frame 600. The foot-end side rails 904,however, remain unmoved irrespective of movement of the head section702, seat section 704 or foot section 706 of the deck support 708.

With particular reference to FIGS. 41, 42, 44 and 45, each of themovable side rails 902, 904 for use with the bed 100 according to thepresent invention generally comprises a side rail body 909 and a siderail body support, the latter illustratively comprising two or moresupport arms 910 pivotally coupled between the side rail body 909 and aguiding mechanism 914 disposed within a cross member 917 configured forfixed attachment to the bed frame structure (e.g to deck support 700 forhead-end side rails 902 and to load frame 600 for foot-end side rails904). A first end of each support arm 910 is pivotally connected to theside rail body 908 in a longitudinally spaced apart relationship usingan upper pivot 912, and a second end of each support arm 910 ispivotally connected to a guiding mechanism 914 through a lower pivot 916operatively engaged thereto in a longitudinally spaced apartrelationship. The guiding mechanism 914 is coupled to a cross-member 917connected to either the deck support head portion 702 (head-end siderails 902) or the load frame 600 (foot-end side rails 904).

With added reference to FIG. 49, each of the lower pivots 916 includes aradial protrusion 918 configured to engage with a groove 920 in theguiding mechanism 914. When the lower pivots 916 are rotationally moved,the radial protrusions 918 are guided by the grooves 920 therebycreating a transverse transitional movement of the pivots 916 along thepivot slots 922 of the guiding mechanism 914 resulting in the transversemovement of the side rail body 909 towards and away from the bed 100,during the lowering and raising movement, respectively, of the siderails 902, 904.

In one embodiment, each support arm 910 is configured to have a shapewith a width greater at the first end 924 than at the second end 926thereof. The side rail body 909 is movable between a deployed positionand a stowed position through clock-type rotational movement in a planesubstantially vertical and substantially parallel to the longitudinallength of the bed 100. As a result of the shape of the support arms 910,the side rail angle defined between each support arm 910 and the bottomedge of the side rail body 909 remains obtuse at all times during therotational movement of the side rail body 909. This configurationeliminates pinch points created between each support arm 910 and thebottom edge of the side rail body 908, which typically occur whentraditional support arms are used.

Side Rail Body and Support Arms

In FIGS. 41, 42, 44 and 45, showing one embodiment of the head-end siderails 902 and foot-end side rails 904, the side rail bodies 909 ofhead-end and foot-end side rails 902, 904 are each connected to twosupport arms 910 through two respective upper pivots 912. Two respectivelower pivots 916 are used to connect the other ends of the two supportarms 910 to a cross-member 917. The distinctive shape of the supportarms 910 illustrated herein is an example of a configuration designed toavoid the creation of pinch points between the support arms 910 and thelower side of the side rail body 909 during movement of the side rail902, 904. In this embodiment, the side rail body 909 is coupled to thesupport arms 910 in a manner allowing the side rail body 909 to bereplaced or changed if damaged or to suit different needs, withouthaving to change the complete side rail 902, 904.

In general, a locking mechanism 928 (FIG. 45) is provided (shown ingreater detail in FIG. 50), in one embodiment to lock the side rail(s)902, 904 in a deployed or raised position, and a release system 930therefor is located on the side rail 902, 904 such that an operator mayselectively lower the side rail(s) 902, 904 when needed. As will beappreciated by the person skilled in the art, the location of therelease system may be designed according to its intended use. Forexample, where it is preferable to limit the use of the lockingmechanism to the caregiver or someone else other than the person on thebed, the release system can be configured and located on the side railbody support (e.g. support arms 910) where it cannot be operated by theperson on the bed 100. This configuration is useful for security andsafety reasons. The side rail locking mechanism 928 (FIG. 45) will bedescribed in greater detail below with reference to FIG. 45.

With reference to FIGS. 47A to 47D and 48A to 48D, interior side andperspective views of a foot-end side rail 904, in accordance with oneembodiment of the present invention, are illustrated for differentpositions from a fully deployed position (FIGS. 47A and 48A) to a fullystowed position (FIGS. 47D and 48D). In this embodiment, it can beclearly identified that the angle formed between each support arm 910and the bottom edge of the side rail body 909 remains obtuse at alltimes during the rotational movement of the side rail body 909. Asdiscussed above, the person of skill in the art will understand that theabove and following discussion applies equally to the head-end siderails 902. This obtuse angle increases as the side rail body 909 islowered. Further, support arms 910 pivot in a counter-clockwisedirection (as viewed in FIGS. 47A-47C) when side rail body 909 islowered.

The side rail body 909 can he made for example from plastic or othersynthetic materials, which can be molded, while the side rail bodysupport 911 can be made for example of aluminum, aluminum alloys or anyother material with a desired level of strength. These materials areprovided solely as examples and the choice of materials used for theseparts can vary according to various considerations such as weight,strength, appearance, durability and sturdiness for example, as will bereadily understood by the person skilled in the art.

In the illustrated embodiments of the barrier system 900, the shape ofthe support arms 910 the characteristics of provides advantageouscharacteristics. The person of skill in the art will appreciate thatseveral similar shapes for the support arms 910 can be used, theseshapes sharing the common characteristic that the width of the supportarms is greater at the upper ends 924 (operatively connected to theupper pivots 912) than the lower ends 926 (operatively connected to thelower pivots 916) so that the angle defined by the lower edge of theside rail body 909 and the support arms 910 remains obtuse at all timesduring the operation of the side rails 902, 904, thereby eliminatingpinch points during operation of these side rails. For example, possibleshapes for the support arms may include substantially triangular (e.g.as illustrated herein), trapezoidal, round, possibly comprising sidescurved in a convex or concave manner, etc. To achieve theabove-described effect of eliminating pinch points, the location of theconnection between the upper ends 924 of the support arms 910 and theupper pivots 912 should be proximal to the rotational side of thesupport arms 910 which faces the rotational movement when the side rail902, 904 is moved from the deployed position to the stowed position, asillustrated in FIGS. 47A to 47D and 48A to 48D for the foot-end siderails 904. Similar geometry also applies for the head-end side rails902.

FIGS. 47B, 47C and 48B, 48C are detailed interior side and perspectiveviews of a foot-end side rail 904 at intermediate positions. The angleformed by the bottom edge of the side rail body 909 and the support arms910 remains obtuse until it is eliminated when the side rail body 909 islowered to a point where the upper pivots 912 are substantially alignedhorizontally to the lower pivots 916 (shown in FIGS. 47C and 48C).

Furthermore, as introduced above in accordance with one embodiment ofthe present invention, the side rail body 909 can be moved laterallytowards and away from the center of the bed 100 as the side rail 902,904 is stowed and deployed, respectively, in order to minimize the widthof the bed 100 when one or more side rails 902, 904 are not in use andconversely maximize the patient's surface lying surface 800 when in use.In this embodiment, the vertical and lateral movement of the side railbody 909 takes place through a single movement during operation of theside rail 902, 904 thereby decreasing the effort and separate actionsrequired for operation of these side rails.

Guiding Mechanism and Cross-member

With reference to FIGS. 41, 42, 44, 45 and 49, the side rail body 909 ispivotally connected to two support arms 910 through a pair of upperpivots 912. The two support arms 910 are pivotally connected to guidingmechanisms 914 through a pair of lower pivots 916, the guidingmechanisms 914 operatively connected to a cross-member 917. A radialprotrusion 918 located on each lower pivot 916 is operatively coupled toa bearing assembly 932 which is operatively engaged with a groove 920 ofthe guiding mechanism. The bearing assembly 932 operatively coupled tothe radial protrusion 918 reduces the frictional coefficient during theoperation of the side rail 902, 904 considerably diminishing the wear ofthe radial protrusion 918 and the edges of the groove 920. Any kind ofconventional bearing assembly can be used for this purpose. The shapeand size of groove 918 can vary depending on the desired lateraltransitional movement of the lower pivots 916 along the pivot slots 922of the guiding mechanism 914. The rotational movement around the lowerpivots 916 which occurs during operation of the side rail 902, 904results in the transverse movement of the lower pivots 916 andtranslates into a transverse movement of the side rail body 909 towardsor away from the longitudinal centerline of the bed 100. In oneembodiment, the distance between the side rail body 909 and the decksupport 700 (head-end side rail 902) or the load frame 600 (foot-endside rail 904) is at its maximum in the deployed position.

The characteristics of the guiding mechanism 914 can be configured inseveral ways. For example, the guiding mechanism 914 can be cast in asingle component, incorporating the cross-member 917. It can also bemachined from a single piece of material. Some of the advantages of suchembodiments are reduced costs of production, simplified installation andstructural integrity of the guiding mechanisms 914 and the cross-member917. The guiding mechanism 914 and cross-member 917 can also be formedfrom several parts. For instance, the areas immediately surrounding thegrooves 922 of the guiding mechanism 914 can be made from parts distinctfrom the rest of the guiding mechanism 914. Given that these sections ofthe guiding mechanism 914 are the areas which will sustain the heaviestwear due to the friction between the radial protrusions 918 located oneach lower pivot 916 or the bearing assembly 932 operatively coupled tothe radial protrusions 918, it is desirable to have these sectionsseparate from the rest of the guiding mechanism 914 and the cross-member917 in order to replace only the damaged sections when needed instead ofreplacing the whole guiding mechanism 914 or cross-member 917. Thisaspect of the invention is also useful to replace the sectionsimmediately surrounding the grooves 920 of the guiding mechanism 914 tochange the configuration of the grooves 920 for different uses of theside rail 902, 904 with the same bed 100. The shape of the guidinggrooves 920 themselves can vary to accommodate various needs and variouslying surfaces 800 the side rail 902, 904 is to be used with. Forexample, the grooves 920 can be linear, curved, angled or a combinationthereof, as long as the guiding grooves 920 of a same side rail 902, 904are substantially identical and have the same orientation.

The embodiment illustrated in FIG. 49, for example, has guiding grooves920 which have a substantially longitudinally linear portion followed bya curved portion. When a rotational force is applied to the side rail902, 904, there is no lateral movement until the radial protrusions 918engage with the curved portions of the guiding grooves 920. When theradial protrusions 918 reach the beginning of the curved portions of theguiding grooves 920, the top of the side rail body 909 is located lowerthan the side of the deck support 700 (head-end side rails 902) or loadframe 600 (foot-end side rails 904) so that once the radial protrusions918 engage with the curved portions of the guiding grooves 920, the siderail body 909 is free to translate laterally closer to the center of thebed 100.

Other embodiments where the radial protrusion 918 and bearing assembly932 are in different positions during the lateral translation movementare also provided. The preceding is merely one example of possibleconfigurations of the guiding grooves 920. The guiding grooves 920 canhave curved portions curving towards or away from the cross-member 917,or any combination of curved and linear portions. For example, a guidinggroove 920 can have two curved portions curving towards the cross-member917 separated by a linear portion such that a rotational force appliedto the side rail body 909 will result in a lateral movement translatingin the side rail body 909 being closer to the center of the bed 100 whenin a fully deployed position or fully stowed position and the side railbody 909 will be further from the center of the bed 100 when intransitional positions. It will also be appreciated that differentgroove configurations may apply to different side rails, for example, tohead-end and foot-end side rails 902, 904 respectively.

In a further embodiment of the invention, the guiding grooves 920 arelocated on the pivot shaft to operatively engage with one or moreprotrusions coupled to a bearing assembly, extending from the inside ofthe pivot slot 922.

In one embodiment the guiding mechanism 914 and the cross-member 917, orthe different components thereof, as the case may be, can be made ofseveral materials. Characteristics such as weight-to-strength ratio,hardness, wear resistance and corrosion resistance (corrosion fromairborne corrosive agents, air and cleaning solvents and bodily fluidsusually found in a hospital/medical environment) should be givenconsideration when choosing the materials to be used in themanufacturing of the guiding mechanism 914 and the cross-member 917 orthe different components thereof. One example of an appropriate materialfor the cross-member 917 is aluminum for its lightweight and resistanceto corrosion. However, other parts such as the areas immediatelysurrounding the grooves 920 of the guiding mechanism 914 and the slots922 for the lower pivots 916 can be made from other materials toaccommodate the higher frictional abrasion on such parts and thereforebeing more prone to wear. Materials with a high resistance to wear, suchas steel, stainless steels or ferrite alloys for example, can be usedfor making these parts. Other parts of the side rail mechanism can bemade from further different materials and are not limited in any way tothe materials used for the guiding mechanism 914. The various parts ofthe guiding mechanism 914 and the cross-member 917 can compriseinterlocking mechanisms provided between the multiple parts to ensurecorrect alignment of these multiple parts during assembly. As mentionedpreviously, for example, the guiding grooves 920 within a same guidingmechanism 914 have to be substantially identical the side rail 902, 904coupled thereto to function properly, requiring parts that are preciselyoperatively connected. Slots, grooves, apertures or fittings, forexample, may be used to interlock the various parts of the side railtogether precisely.

In one embodiment, the operation of the side rails 902, 904 is asdescribed above and illustrated in FIGS. 47A to 47D and 48A to 48D,wherein an exemplary embodiment of the foot-end-side rails 904 areillustrated in transitional positions between a fully deployed position(A) and a fully stowed position (D). In general, the distance betweenthe lower portion of the side rail body 909 and the deck support 700(head-end side rails 902) or load frame 600 (foot-end side rails 904) isgenerally at its minimum in the fully stowed position. In thisembodiment, as shown, an angle between the support arms 910 and thelower edge of the side rail body 909 is generally maintained obtusethereby eliminating pinch points.

In another embodiment (not shown), the pivot shafts of the lower pivots916 engaging with the guiding mechanism 914 are screw-type shafts. Inthis embodiment, the guiding mechanism 914 is designed to have treadsmatching the radial extensions of the screw-type pivot shafts tooperatively receive the radial extensions creating a lateral translationmovement of the pivot shafts through a rotation of the pivot shafts. Thelateral translation movement is away or towards the guiding mechanism914 depending on the orientation of the rotational movement applied tothe shafts. Using this type of screw-type pivot shaft, one or more lowerpivot shafts can be designed to have radial extensions to operatively becoupled to a bearing assembly which can be operatively engaged withtreads of the guiding mechanism 914.

In one embodiment pivot journals or journal bearings can be used betweenthe pivot shafts and their corresponding pivot slots 922. The pivotjournals or journal bearings help reduce significantly the wearing ofthe pivot shafts and the corresponding pivot slots 922 while alsoreducing high contact stresses and strain. Within the parameters of theembodiments, of the present invention, this is especially useful whenapplied to the upper pivots 912 since they sustain the heaviest strainduring operation of the side rail mechanism due to their relationalposition from the lying surface 800.

During operation of the side rail mechanism according to an embodimentof the present invention, a rotational force is applied to the side railbody. However, while operating the side rail mechanism, there willalways be a certain amount of substantially longitudinal force appliedto the mechanism possibly resulting in binding at the pivot points. Thiscan happen as a result of the application of a force to the side railthat is not aligned with the rotation centered with the lower pivots916. In order to address and minimize such a result, an embodimentprovides a first upper pivot slot being slightly oblong-shaped while thesecond upper pivot slot is circular. This feature is particularlyadvantageous for one hand operation of the side rail where the forceapplied to the side rail 902, 904 will likely not be aligned with therotational movement of the side rail 902, 904.

In one embodiment, a first upper pivot slot is an oblong slot oraperture for receiving a first upper pivot shaft. The oblong aperturehas a minor vertical axis with a diameter substantially equivalent tothe diameter of the first upper pivot shaft and a major horizontal axishaving a diameter greater than the diameter of the minor axis anddefined by a left extent and a right extent. The major axis of theoblong aperture is substantially parallel to a line drawn between thecenters of the first and second upper pivot shafts. The side rail body909 further includes a regular aperture, e.g., a circular slot, forclosely receiving a second upper pivot shaft. As the support arms 910rotate about the first and second lower pivots 912, the first upperpivot shaft shifts laterally within the oblong slot. As the side railbody 909 is further rotated to a zero point (e.g. shown in FIGS. 47C and48C) the support arms 910 are nonparallel to each other to ease thepassage of the side rail body 909 through the zero point. The oblongslot allows for this nonparallel arm geometry without binding. In thelowermost position, the first upper pivot shaft has shifted from theleft extent of the oblong slot in to the right extent of the oblong slot(or vice versa depending on the orientation of the side rail and itsdirection of rotation).

A sequence of movement of the first upper pivot shaft within the oblongslot is generally as follows: in the uppermost side rail position, thefirst upper pivot shaft is at the left extent of the oblong slot. As theside rail body is moved from the uppermost position (e.g. FIGS. 47A and48A) to the lowermost position (e.g. FIGS. 47D and 48D), the first upperpivot shaft shifts from the left extent toward the right extent of theoblong slot. The distance between the first upper pivot shaft and thesecond upper pivot shaft thereby decreases as the side rail body 909 ismoved from its uppermost position to its lowermost position. Thismovement further acts to ease any binding that might occur.

As noted above, foot-end side rail may be provided with a visualindicator that provides a quick reference to the inclined angle of thehead section when the head section is pivoted. Referring to FIG. 45A,the visual indicator 905 b comprises a static or stationary indicatorwithout any moving parts that includes a plurality of references marks905 a that correspond to selected angles. As shown, those angles mayinclude 0, 15, 30, 45, 60 and 80 degrees, for example. The indicator 905may be formed, such as by molding or marking on the outer surface of theside rail body or may be applied thereto by a cover, such a thin sheetor membrane 905 b, which may be applied and secured to the body of theside rail by, for example an adhesive. For example, membrane 905 b maybe in the form of a sticker that has an adhesive rear surface 905 c. Inaddition to being formed on a membrane, which is applied to the body,the visual indicator may be formed or provided on a plate, such as metalplate, including a steel plate, which is mounted to the body. Forexample, the plate may be magnetically mounted or adhesively mounted ormounted by fasteners to the body, or the plate may be insert molded withthe body.

As would be understood, when the head-section of the bed is inclined theedge of the lying surface or an edge of the deck itself may be used as areference line against the reference marks so that the angle of thehead-section can be determined with a quick glance.

Locking Mechanism

As introduced above, and as illustrated the embodiments of FIGS. 42, 43,45 and 50, each side rail 902, 904 may include a locking mechanism 928configured to allow the side rail 902, 904 to be locked in a specificposition. The locking mechanism 928 generally includes a locking arm 934pivotally mounted on the side rail body 909 at a first end and having alocking tooth 936 at a second end. The locking arm 934 is biaseddownwardly by a spring 938 for the locking tooth 936 to engage with alocking cog 940 that is mounted on the shaft of one of the upper pivots912. The locking cog 940 is affixed to this pivot shaft in a manner tobe rotatably fixed with respect to its support arm 910. The position inwhich the side rail body 909 is locked is determined by the position ofthe locking cog 940. The locking mechanism 928 further includes a lockrelease handle 942 pivotally connected to the side rail body 909 by apivot pin 944. The lock release handle 942 includes a contact pad 946adapted for grasping by an operator and a locking arm engagingprojection 948 configured to engage the underside of the locking arm934.

In one embodiment, the lock release handle 942 and contact pad 946 areconfigured so that as the operator grasps the contact pad 946, theoperator is applying the force in a centered position between the shaftsof the upper pivots 912 and coinciding with the center of gravity of theside rail body 909. The operator is thus able to grasp and support theside rail body 909 in a balanced fashion, disengage the locking arm 934,and lower the side rail body 909, in a one-handed operation.

In one embodiment, the side rail body 909 is locked in its uppermostposition, wherein the locking cog 940 is engaged by the locking tooth936 of the locking arm 934. In this illustrated uppermost position, thesupport arms 910 are not fully upright, but are positioned at an anglefrom the vertical. In the alternative, the locking tooth 936 and thelocking cog 940 can be configured to secure the support arms 910 in avertical orientation. Furthermore, the side rail body 909 may include anintegrally molded stop 950 adjacent to the locking cog 940 to preventfurther rotation of the locking cog 940 from the lowermost positionshown in FIGS. 47D and 48D, for example.

As shown in FIG. 50, the side rail body 909 is prevented from rotatingto a lower position due to the interaction of the locking tooth 936 ofthe locking arm 934 with the locking cog 940. As will be understood bythe person skilled in the art, as an operator draws upwardly on the lockrelease handle 942 by contacting the pad 946, the lock release handle942 pivots about the pin 944 and the projection 948 engages the lockingarm 934. The locking arm 934 is raised against the bias of the spring938 so that the locking tooth 936 disengages the locking cog 940. Thisfrees the side rail mechanism to rotate to a lower position.

In order to raise the side rail body 909, an operator can grasp the siderail body 909 at any convenient location. When the side rail body 909 isnot in the locked position, the locking arm 934 is disengaged from thelocking cog 940, the support arm 934 thereby being free to rotate. Inone embodiment, any off-center force exerted by the operator does notcause binding due to the non-parallel configuration of the support armsand the oblong slot, discussed above.

In one embodiment, the locking mechanism 928 further comprises a sensor951, such as an inclinometer or the like (e.g. see FIGS. 42 and 45), fordetecting and/or monitoring an inclination/orientation of the lockingarm 934. For instance, when the locking arm 934 of a given side rail902, 904 engages the locking cog 940, a signal is provided to thecontrol system 1000 to indicate that the given side rail is up andsecured. When the locking arm 934 is released, the signal may change andindicate that the side rail 902, 904 is either down from its uppermostposition, or that the side rail is still up but unlatched, and therebynot secured. As will be described in greater detail below, data acquiredusing this and other such sensors disposed on various parts of the bedcan be used in calculating and monitoring various characteristics of thebed 100 and/or of a patient lying thereon. As will be apparent to theperson skilled in the art, the sensor 951 can be mounted elsewhere onthe locking mechanism 928 without departing from the general scope andnature of the present disclosure. A sensor may also, or alternatively,be mounted to the side rail body 909, support arms 910, etc. to providesimilar or complementary data.

Damper Mechanism

In one embodiment, the movable side rail apparatus incorporates a dampermechanism 952 (FIG. 47B) to achieve a smoother movement of the side railbody 909, improve the feel for the user of the side rail 902, 904,eliminate noise and possible damage or injury caused when a side railbody 909 is dropped from the raised position, and improve the feel ofquality of the side rail 902, 904.

FIGS. 47A to 47D and 48A to 48D illustrate various views of the damper954 when the angle 956 between the support arm 910 and the cross-member917 (also called the side rail angle) is 70, 30, 0 and −35 degreesrespectively. As the angle 956 diminishes, the side rail body 909 lowersrelative to the cross-member 917. The cross-member 917 is fixed toeither the deck support 700 (for the head-end side rail 902) or the loadframe 600 (for the foot-end side rail 904) and therefore may not movewhen the side rail body 909 moves.

The damper mechanism 952 comprises a spring 958, link member 960 anddamper 954 operatively connected with the cross-member 917 of the siderail 902, 904. One end of the spring 958 is coupled to the cross-member917 and the other end is coupled to the link member 960. The link member960 is coupled to the cross-member 917 with links 962 that moveproportionally to the rotation of the support arms 910. One end of thedamper 954 is coupled to the cross-member 917 and the other end iscoupled to a link 962.

The damper mechanism 952 facilitates the downward, lowering movement ofthe side rail body 909. The damper mechanism 952 prevents the side railbody 909 from descending to a lower position at an undesired fast ratedue to the gravitational force acting on the side rail body 909 and,therefore, acts as a counterbalance device. The skilled worker willappreciate that the tension in the spring 958 changes with movement ofthe side rail body 909 and damper 954. For example, as the side railbody 909 descends, the link member 960 displaces longitudinally, therebyincreasing tension in the spring 958.

Based on the shape of the support arm 910 and the angle 956 it formswith the cross-member 917, the side rail angle 956 may vary at any givenpoint. In this embodiment, as can be seen in FIGS. 47A and 48A, when theside rail body 909 is fully raised or deployed, the side rail angle isabout 70 degrees and the damper 952 is fully open. At this point, thereis minimal tension in the spring 958.

As the side rail body 909 lowers to a partially deployed position (seeFIGS. 47B and 48B) the side rail angle 956 decreases to about 30degrees, and the link member 960 is displaced horizontally. The damper954 is partially open at this point.

FIGS. 47C and 48C depict a side rail angle 956 of about 0 degrees atwhich point the side rail body 909 is in a partially stowed position.The link member 960 has displaced even further and the damper 954 ispartially closed.

FIGS. 47D and 48D depict the side rail body 909 in a fully stowedposition. The side rail angle 956 is about 35 degrees past thehorizontal and the damper 954 is fully closed. Since the link member 960is at its maximum displacement, the tension in the spring 958 is at itshighest.

The magnitude of effect on the lowering movement is called the dampingcoefficient. For the adjustability of the damping coefficient, thestiffness of the material in the damper 954 may be adjusted, therebyimpacting the damper's degree of damping. The illustrated dampermechanism 952 can use elastomeric pads which may be identified by colorcoding corresponding to the desired damping coefficient. As the dampermechanism 952 of the illustrated embodiments are installed in the siderail mechanism to dampen the downward motion of the side rail body 909(i.e. attenuating the force of gravity on the side rail 902, 904), therange of desired damping coefficients may not be large.

The damper mechanism 952 can further act as a shock absorber bydecreasing the amplitude of the mechanical oscillations (up and downmovement) of the spring 958. As such, the damper mechanism 952eliminates or progressively diminishes the vibrations or oscillations ofthe side rail body 909, thereby resulting in a smooth movement from thefully deployed to the fully stowed positions.

For additional variations that may be incorporated into the side rails,reference is made to copending PCT Pat. Application No. PCT/CA06/01341,filed Aug. 16, 2006, which claims priority to U.S. provisionalApplication Ser. No. 60/760,564, filed Oct. 27, 2005 and to U.S. Pat.No. 6,721,975 to Lemire, issued Apr. 20, 2004, which are incorporated byreference herein in their entireties.

Relative Positioning of Side Rail(s)

In various embodiments, the side rail or side rails 902, 904 arepositioned on a first side of the bed 100 and can be designed to operatein a mirror fashion to the side rail or side rails 902, 904 located onthe other side of the bed 100, where the side rail 902, 904 on one sideof the lying surface 800 would operate in the opposite rotationaldirection (clock-wise/counter clock-wise) to the corresponding side rail902, 904 on the other side of the bed 100 and where the longitudinalmovement of the side rail bodies 909 along the length of the bed 100would be in the same direction. Alternatively, a bed can have otherconfigurations such as one side rail 902, 904 on one side and two siderails 902, 904 on the other. When a bed 100 comprises two side rails902, 904 on a single side (as illustrated herein), the relativerotational movement of these two side rails 902, 904 should be oppositein order to avoid impact therebetween, for example when only one of thetwo side rails 902, 904 is moved between a raised and lowered positionand vice versa. A single bed 100 can have side rails 902, 904 ofdifferent shapes and sizes (e.g. head-end side rails 902 and foot-endside rails 904).

Head/Foot-end Side Rail Assembly

As already discussed, the hospital bed 100 of the present invention canhave a variety of side rail combinations. For example, the bed 100 canhave side rails at the head-end of the bed (e.g. head-end side rails902) or at its foot-end (e.g. foot-end side rails 904), or at both endsof the bed 100. As well, the bed can have side rails 902, 904 on thesame side of the bed 100 or on both sides of the bed 100. In embodimentscomprising a pair of side rails 902, 904, one at each end of the bed(i.e., the head-end and foot-end), the side rails 902, 904 are designedto allow movement of the bed 100 in its various configurations. In otherwords, the side rails 902, 904 are designed to allow relative movementof the components of the bed 100 (e.g. fowler 702, seat 704, and footsections 706 of the deck support 700).

In one embodiment, the bed 100 comprises a pair of side rails 902, 904on at least one side of the bed 100, that are designed to overlap attheir mutually adjacent ends so that no gap exists between them in allpositions of relative movement therebetween and while maintaining agenerally uniform thickness between the head-end of the side rails andthe foot-end thereof. In the illustrated embodiments describedhereinabove, each of the side rails 902, 904 are contained in a planethat is parallel to a vertically upright plane containing a longitudinalaxis of the bed 100. Furthermore, each of the side rails 902, 904 have asubstantially uniform thickness extending over a majority of the lengthof each of the respective side rail components.

With reference to FIGS. 40A, 41, 44, the head-end of the foot-end siderail 904 has a region 964 of reduced thickness facing outwardly awayfrom the plane. The outwardly facing surface of the region 964 extendsin a plane generally parallel to the aforethe plane. Similarly, thefoot-end of the head-end side rail 902 has a region 966 of reducedthickness facing inwardly toward the plane. The surface of the region966 extends substantially parallel to the plane. As illustrated in FIG.40A, for example, the opposing surfaces 964, 966 overlap and are in aside-by-side arrangement so as to prevent the formation of alongitudinal gap between the respective side rails 902, 904. Inaddition, the total thickness of the head-end of the foot-end side rail904 and the foot-end of the head-end side rail 902 is of a thicknessgenerally conforming to the overall uniform thickness of each of therespective side rails 902, 904. In embodiments comprising a pair of siderails 902, 904 on each side of the bed 100, the side rail configurationis duplicated on the other side of the bed 100.

In one embodiment, the region 964 of reduced thickness of the foot-endside rails 904 is generally L-shaped, the short leg of the L beingprovided at the head-end and the long leg of the L extendingcoextensively with the side rail 904 adjacent the upper edge thereof.The width at about the midlength of the side rail 904 is greater thanthe width immediately adjacent the short leg of the L of the region 964.The region 966 on the head-end side rail 902 is generally rectangularand has a generally uniform width in the horizontal direction over thelower half and another width over the upper half.

As would be apparent to a person skilled in the art, when the headsection 702 and the seat section 704 of the deck support 700 are atabout 0° relative to the horizontal, the foot-end of the head-end siderail 902 overlaps the head-end of the foot-end side rail 904, asillustrated in FIG. 40A, for example. As the head section 702 isadvanced from the horizontal position to a raised position, the head-endside rail 902 is shifted toward the foot-end of the bed 100 relative tothe foot-end side rail 904 while the overlapping regions 964, 966 remainoverlapping. As the head section 702 advances through further inclinedpositions, as illustrated in FIGS. 5 and 6 for example, the foot-end ofthe head-end side rail 902 moves along the long leg of the L-shapedregion 964 so that the foot-end of the head-end side rail 902 isreceived into the larger width section of the region 964. It will benoted that there may remain a gap between a top edge of the head-endside rail 904 and a head-end facing edge of the region 964 at themidlength portion of the foot-end side rail 904.

Side Rail User Interfaces

As introduced above, various user interfaces may be used to controldifferent features of the bed 100, for example the bed's optional drivemechanism 204 (e.g. see FIG. 10), brake system 206 (e.g. see FIG. 11),deck support actuation mechanism(s) (e.g. see FIGS. 32 to 39), as wellas provide various visual indicators as to a status of these and othersystems operating in cooperation with the bed's structural elements(e.g. barrier system 900, networked components, peripheral devices,etc.). Other controls provided by such interfaces may include controlsof various patient comfort, service and/or entertainment features, suchradio, TV, nurse station calling system, phone, etc.

With reference to FIGS. 40A, 40B, 43 and 46, showing an illustrativeembodiment of the bed's barrier system 900, a number of user controlinterfaces are provided on or within the side rails 902, 904 to providea user access to various controls and/or status indicators. For example,the head-end side rails 902 illustratively comprise a first interfacepanel 990 proving both an outer interface 991 for use by a medicalpractitioner, for example (e.g. see FIG. 55), and an inner interface 992for use by the patient (e.g. see FIG. 56). The head-end side rails mayfurther comprise a second interface panel 993 providing an outerinterface 994 for used by a medical practitioner, for example (e.g. seeFIG. 57). In addition, the foot-end side rails 904 may also comprise aninterface panel 995 (FIG. 1), providing a further outer interface foruse a medical practitioner for example, and providing similar featuresas illustrated in the FIG. 57 for the head-end outer interface 994.

Headboard and Footboard

The headboard 906 and footboard 908, illustrated for example in FIGS.40A and 40B in accordance with one embodiment of the present invention,may be individually molded using a fluid injection molding process, suchas gas-assist injection molding process or water injection moldingprocess. Gas-assist injection molding is a well-known process thatutilizes an inert gas (normally nitrogen) to create one or more hollowchannels within an injection-molded plastic part. During the process,resin such as polypropylene is injected into the closed mold. It isunderstood that any other suitable material, such as ABS, nylon, or anyother resin compatible with the process may be used. At the end of thefilling stage, the gas such as nitrogen gas is injected into the stillliquid core of the molding. From there, the gas follows the path of theleast resistance and replaces the thick molten sections with gas-filledchannels. Next, gas pressure packs the plastic against the mold cavitysurface, compensating for volumetric shrinkage until the partsolidifies. Finally, the gas is vented to atmosphere or recycled.Advantages to using such a process over other molding processes areknown to a worker skilled in the art.

Headboard

The headboard 906 is illustratively made of one piece, as depicted inFIGS. 40A and 40B in accordance with one embodiment of the presentinvention. This mold is designed to produce a curved removable headboard906 which is sturdy, very light, and easy to access and manipulate bythe user. Further, headboard 906 may be removed and used as a CPR board.For example, the headboard may be removed from the bed and then insertedunder the patient so that a medical professional can do CPR on thepatient. For example, the nurse or medic may insert the headboardbetween the patient and the mattress, which provides a stiff surface sothat the patient will not sink into the mattress and the medicalprofessional can properly apply CPR.

Typically, medical professionals require access to the head section of ahospital bed 100 to position equipment proximate to the patient's head.In urgent situations, such as when the patient requires immediatemedical attention, immediate access to the head section is oftenrequired. In both such situations, the headboard 906 is desirably movedaway from the access area or completely removed from the bed 100. For aheadboard 906 that is removed from the bed 100, it is desirable thatsuch headboard 906 be as light as possible, while still maintainingsufficient structural integrity. Once removed from the bed 100, theheadboard 906 is typically placed within the near vicinity, such as byleaning against a support surface such as a wall proximate to the bed100.

Since the headboard 100 of the present embodiment is a one-piece unit,it is less costly to manufacture than headboards which have multipleparts and require assembly. With no additional parts to attach to theheadboard 906, there are also fewer parts that are subject to mechanicalfailure. As will be apparent to the person skilled in the, other typesof headboards may still be considered herein without departing from thegeneral scope and nature of the present disclosure.

The design of the headboard mold of use in manufacturing the headboard906 of the present embodiment is unique. The headboard 906 has agenerally rectangular shape. A generally tubular channel 906 a(generally shown in phantom in FIG. 38), which is hollow, borders theheadboard 906 at both sides and the top, tapering inwards towards thebottom and ending in two ends which project below the generallyrectangular portion of the headboard 906. Proximate to each end is agenerally oval post 968 (e.g. see FIGS. 17A, 28, and 32) for removablymounting the headboard 906 into mounting sockets 452 provided in thehead-end structure 450 of the intermediate frame 400 (described above).

Optionally, in order for the headboard 906 to avoid being damaged whenit is resting on the floor against a wall for example, a cap, cover orplug made of a non-stick material such as rubber, can be fitted aroundeach post. Additionally, the plug may ensure a snug fit into themounting sockets 452 and minimize wear on the posts 968. The plug can beattached to or molded into the headboard 906.

The generally rectangular portion of the headboard 906 comprises a flatthin layer of resin or headboard skin 906 b, which covers and joins thetubular channel, to form a hollow but rigid headboard with asubstantially smooth joint-less surface to minimize areas likely tocollect microorganisms and allow their growth as well as to facilitatecleaning of the headboard surface. In one embodiment of the presentinvention, the headboard skin has a thickness of about ⅛ inch. It willbe appreciated that the thickness of the headboard skin and tubularchannel is proportional to the amount of material required and theweight of the headboard 906. The headboard 906 can also be translucentor transparent for easier monitoring of the patient and bettervisibility.

In one embodiment, the headboard 906 has a gradual concave shape suchthat when the posts 968 are fitted into the mounting sockets, the centerof the headboard skin is furthest from the bed's head section. Giventhat the headboard 906 is formed by a process, which uses a minimalamount of resin, the concave shape in addition to the integrated tubularchannel provides additional stability to the headboard 906.

In operation, users, such as medical professionals, can seize thetubular channel at both sides of the headboard 906 and lift upwards forremoval of the headboard 906. Installation requires lining up over andinserting each post 968 inside the mounting sockets 452. Optionally, oneor more holes or transverse openings 970 of various shapes and sizes canbe located within the skin to create handles allowing users toconveniently grasp the headboard 906 prior to removal or installation.In one embodiment the headboard comprises handles that can withstand atleast 150 lbs. of force.

Footboard

FIGS. 40A, 40B and 51 to 53 depict a footboard 908 in accordance withone embodiment of the present invention. The footboard 908 is formedusing a similar injection molding process as the headboard 906. Thefootboard 908 also has a generally rectangular shape. A generallytubular channel 908 a (shown generally in phantom in FIG. 1), which ishollow, borders the footboard 908 at both sides and the top, taperinginwards towards the bottom and ending in two ends, which project belowthe generally rectangular portion of the footboard.

Proximate to each end is a generally oval 972 post (e.g. see FIG. 39)for removably mounting the footboard 908 into mounting sockets 752 (e.g.see FIGS. 37 and 39) provided in the foot-end structure 750 of the decksupport's foot portion 708. Similar optional plugs as described abovewith reference to the headboard 906 may be used and fitted around eachfootboard post 972.

The generally rectangular portion of the footboard 908 has a thin layerof resin or footboard skin 908 b, which covers and joins the tubularchannel, to form a hollow but rigid footboard with a substantiallysmooth joint-less surface to minimize areas likely to collectmicroorganisms and allow their growth as well as to facilitate cleaningof the footboard surface. In one embodiment of the present invention,the footboard skin has a thickness of about ⅛ inch. Optionally, one ormore holes or transverse openings 974 of various shapes and sizes can belocated within the skin to create handles that allow users toconveniently grasp the footboard 908 prior to removal or installation.In one embodiment the footboard 908 comprises handles that can withstandat least 150 lbs. of force.

In one embodiment, as shown in FIGS. 1 to 8, and 51 to 53, the footboard908 is molded so as to allow attachment of a control console 976 (e.g.see FIGS. 1 and 54). The console 976 has a display and/or interface 978(FIG. 51A) with which the user can interact, as described furtherherein. When a control console 976 is attached to the footboard 908, thefootboard 908 may further comprise a back panel 980 to secure andprotect the control board's electronic components.

The console 976 can be of any shape or size. The board zone is generallystructured to complement the interface. Users such as medicalprofessionals, require an unobstructed view and access to the console976. In one embodiment depicted at FIGS. 51 to 54, a generallyrectangular control console 976 can be located at the board zone in theupper middle half of the footboard 908. The console 976 may optionallybe positioned at an angle (FIGS. 51B, 52) relative to the vertical suchthat a user peering down at the console 976 from a position above isafforded an unobstructed perspective of the console 976.

In FIG. 58, an exemplary panel interface 996 is shown comprising anumber of control user actuatable devices, such as a buttons, andindicators 997 and an LCD display 998, which may provide interactivecontrol capabilities to a user thereof (e.g. touch screen functions,etc.). FIGS. 59A to 59D provide some exemplary screen shots provided bythe LCD display 998.

Footboard Connector

Removable components of the bed of the present invention, such as thefootboard 908 (and optionally headboard 906), may require electricalconnection when attached to the bed. In one embodiment of the invention,the bed comprises male and female connector portions, where one portionis integrated inside the removable component and the mating portion ofthe connector is positioned within the bed. The connectors areconfigured in order that upon mechanical connection between theremovable component and the bed, the male and female connector portionsmate thereby forming the desired electrical connection. For example, afirst portion of the connector can be positioned within a footboardmechanical support and the mating connector component can be positionedwithin the footboard support structure on the bed. When the footboard isconnected to the bed, the footboard mechanical support is inserted intothe footboard support structure thereby allowing complementary connectorportions to mate thereby forming the electrical connection. For example,with reference to FIGS. 39 and 53, a first portion of the connector 794is positioned on a foot-end structure 783 upon which the footboard 908is mounted, and the second portion of the connector 984 (FIG. 53) isprovided within a bottom portion of the footboard 908 such that, whenthe footboard posts 972 are coupled to the coupling sockets 784 of thefoot-end structure 783, the first and second portions of the footboardconnector 794, 984 are connected thereby provided a power and/orcommunicative link between the footboard 908 and the power/informaticshoused within the foot section 706. It will be appreciated that asimilar feature may be integrated within the headboard 906 and head-endstructure 450 (e.g. see FIG. 31) to which it is mounted.

Integration of the connectors within the removable components (e.g. theheadboard 906 and footboard 908) and the bed 100 allows the connectorsand wires to be concealed within the footboard/headboard mechanicalsupports and the footboard/headboard support structures, therebyconcealing the connection from view and protecting the connector fromdamage upon removal of the footboard/headboard. In this way, connectoralignment is improved, as well as bed aesthetics. In addition, locatingthe connector internally also better protects the connector and attachedelectrical wires from misalignment, loss or damage.

Surfaces Enabling Ease of Disinfection

There are different types of decontamination procedures for hospitalbeds (excluding mattresses, mattress covers and bedclothes) depending onthe level of decontamination required. These decontamination proceduresconsist of two processes, cleaning and disinfection. Cleaning proceduresdo not destroy microorganisms, but physically remove microorganisms,organic matter and visible soiling through use of a general-purposedetergent and water. Disinfection procedures destroy microorganisms butnot bacterial spores through the use of chemical disinfectants. Chemicaldisinfectants generally used on beds include iodophors, phenolics,quats, and chlorines.

Given the above, hospital beds of the present invention are designed toallow for efficient decontamination. For example, the surfaces of thebed are able to withstand frequent contact with disinfectants andcleaners used in the decontamination procedure. This is particularlytrue for high contact surfaces such as bedrails and adjustment knobs. Aswell, the surfaces of the bed of the present invention are designed tobe smooth so as to minimize the surface areas likely to collectmicroorganisms and allow their growth as well as to facilitate drying.Furthermore the bed of the present invention are designed to minimizethe number of openings into areas that are not easily accessible (i.e.joints, or hollow elements) into which microorganisms can enter andflourish. In one embodiment, the bed comprises modular side railswhereby the modules are sealed against the entry of microorganisms. In afurther embodiment of the invention, the side rail modules are sealedoff from the environment with a removable sealing means. Removablesealing means that are contemplated include, for example, covers, suchas magnetic sided covers or reusable stickers. As well, the bed of thepresent invention is designed such that high contact surfaces, such asbedrails and adjustment knobs, are easily removable so that they can besubjected to more intensive decontamination procedures, for examplesterilization, thus allowing for the removal of bacterial spores ifnecessary. Easy removal of mattresses and bedding materials is alsocontemplated by the present invention.

Referring to FIGS. 43A-43D, side rail 902 includes a rail body that isformed from a housing base, which houses most of the components formingthe guide mechanisms for raising or lowering the side rail, and ahousing cover 977 that mounts over the housing base 975 so that thesecomponents are generally not visible to the patient. Housing base 975and housing cover 977 are optionally formed with transverse openings 902a that provided hand holds or gripping surfaces. As noted above, siderail 902 may incorporate one or more control interfaces, which arelocated in housing base 975 and located in openings provided in thehousing cover 977 of the side rail body. In addition housing base 975may house a speaker S, which is aligned with an opening provided in thehousing base 975 and oriented to face the patient.

Optionally, the gaps formed between the housing cover 977 and thehousing base 975, as well as the gaps that are formed between theinterfaces in the surface of the housing cover 977 may be sealed by oneor more sealing covers 979 a, 979 b, and 979 c. Covers 979 a, 979 b, and979 c may comprise removable sealing covers, such as membranes orstickers that are applied by an adhesive, such as an adhesive layer thatreleases when pulled. As a result, the covers are flexible and furtherare easily contoured and shaped to fit and cover almost any surface ofthe bed. For example, sealing cover 979 a may extend down to the loweredge of the side rail and follow the contour of the handgrip 902 bprovided at the lower edge of rail 902.

As best seen in FIG. 43C, housing cover 977 may include recessed areasaround the openings for the control interfaces 990 and 993 with a rimmedsurface that extends around each opening. In this manner when covers 979b and 979 c are located and positioned over the control interfaces, theedges of the covers may be recessed such that the outer surfaces of thecovers are substantially flush with the areas surrounding the openings.Similarly, the perimeter area around sealing cover 979 a may be slightlyraised so that the cover 979 a is also slightly recessed in housingcover 977 and so that its outer surface is substantially flush withperimeter area surrounding cover 979 a. This arrangement greatlyenhances the cleaning of these surfaces and any of the other surfacesthat have such sealing surfaces applied thereto.

In another embodiment, the bed is constructed from materials that do notfavor the growth or adhesion of microorganisms. Exemplary materialswould be known to the skilled person and can include, withoutlimitation, materials that have been treated with an additive which canimpede bacteria or other organism growth on this material, such asMICROBAN™.

II. Power and Control Systems

Powering Bed Electronics with or without a Battery

A means is provided for facilitating the operation of the electronics ina bed under conditions when it is not possible to rely on a battery tosupply the required power for operation.

In one embodiment depicted in FIGS. 37 and 38, power from a remote orexternal power supply or source that is external to the bed, such as aconventional AC source, is fed into separate lines, one to recharge thebattery and another to provide power to the electronic systems. In thismanner, when the apparatus is connected to a power supply other than thebattery, the battery can be recharged as needed and the electronicsystems can operate concurrently with external power, which bypasses thebattery. The battery may be located anywhere within the bed, however, inthe illustrated embodiment of FIG. 38, two batteries are located in thefoot section 708 of the deck support 700.

When the bed 100 is connected to an external power source, theelectronic systems can be accessed immediately independent of theoperability of the internal battery power. The power feed configurationof the bed 100 has the added advantage of preserving the life of thebattery by avoiding problems that can arise when a battery is rechargingand variable power demands are being placed on the recharging battery bythe operation of the bed's electronic systems.

Button Activation for CPR and Trendelenburg on an Alternate EnergySource

The bed of the present invention provides a mechanism for quicklyadjusting the Fowler configuration (e.g. head section 702 of the decksupport 700) of the bed 100, for example, in situations where the fowlerposition needs to be quickly lowered or raised in response to apatient's state. A simple and convenient mechanism to quickly lower theFowler section 702, while utilizing the motor-driven mechanism alreadyin place, obviates the requirement for alternate mechanisms which maytake up valuable room on the bed structure or that are complicatedand/or cumbersome to activate.

In one embodiment, the speed of Fowler movement can be increased byboosting the Fowler actuator voltage, thereby increasing the actuatorspeed. This is illustrated schematically in FIG. 60 where for example,the voltage to the actuator(s) for bed movement is increased from 12V DCto 24 VDC when the user selects a specific function on a control panel(e.g. see FIGS. 55, 58). The temporary increased voltage to theactuator(s) accelerates movement of the bed to the desired position.

One embodiment encompasses user actuatable device activation, such asbutton activation, for CPR and Trendelenburg on an alternate energysource, such as a battery, to transiently increase the voltage suppliedto the motor, such that the motor speed is increased. The power neededto lower the head or Fowler section 702 is low and the relative loadperceived by the motor is less than the actual load due to gravity. Inaddition, the motor can support the low duty cycle of the acceleratedmotion without risk of failure during operation at increased speed. Inthis way, accelerated movement of the Fowler section 702 is quickly andreliably actuated during an emergency with the press of the useractuatable device, such as the button, and is stoppable upon release ofthe user actuatable device. As discussed further herein, a convenientlocation for this function is on a control panel located on the exteriorof the headboard 906. This location enables the caregiver immediateaccess to the patient while placing the patient in the desired position.

As one embodiment relies on a motor-driven mechanism which is already inplace, it also provides a reliable back-up mechanism in which theposition of the bed could be changed at a time and location in whichnormal movement would be impeded. The need may exist such as during apower outage or if the patient were to suffer cardiac arrest while in anelevator, with the bed detached from its conventional power supply.

Movement to the CPR or Trendelenburg positions may be enabled even underpower failure. For example, a battery may be used to provide back-up,for example the CPR. The Trendelenburg positions, for example, may beprovided with a manual override, which can be used in the power failurecondition.

In one embodiment, in order to activate this movement, the correspondinguser actuatable device (such as a button) on one of the control panelsis pushed and maintained. As discussed further herein, a convenientlocation for this function is on a control panel located on the exteriorof the headboard 906. This location enables the caregiver immediateaccess to the patient while placing the patient in the desired position.

Optionally, and in addition to increasing the speed of the Fowlermovement by boosting the Fowler actuator voltage, thereby increasing theactuator's 714 speed, the speeds of the seat section movement and thefoot-end section movement may similarly be increased by boosting theseat section actuator 724 and foot section actuator 734 voltage. Theincreased speed of the seat section and foot-end section, in addition tothe increased Fowler movement speed, to a substantially horizontalposition or a CPR or a Trendelenburg position, allows a user to quicklyand reliably actuate all three deck support sections during an emergencywith the press of a button, the movement being optionally stoppable uponrelease of the button.

A visual indication using lights may also provided which is viewablefrom several positions around the bed 100 in order to indicate lowbattery power.

Zoom Control Algorithm

An automatic control for acceleration and deceleration of the optionalmotorized auxiliary wheel 224 that is used to move the bed 100 isprovided, thereby allowing for variable speeds during bed movement. Theautomatic control function provides movement assistance to users such ashospital personnel moving the bed, thereby reducing the perceived weightof the bed with or without a patient thereon. The zoom control adjuststhe speed of the auxiliary wheels by comparing the drive signal of theauxiliary wheels with the force applied on the push handles by the userpushing the bed, and provides a level of feedback to the user relatingto the natural deceleration of the bed due to frictional losses, forexample. This results in the user having to use less force than isnormally required to move the bed. Furthermore, when the user removeshis or her hands from the push handles, the bed decelerates.Alternately, the headboard may include user actuatable devices that maygenerate signals to the zoom control. Either way, less force is neededto maneuver the bed when the patient is lying on it. As well, bedmovement may be more intuitive since the speed of the bed during patienttransport is controlled by the force applied by the user on the bedhandles or on the bed headboard when pressure based actautable devicesare employed. Thus, the user does not have to push a user actuatabledevice or a pedal to adjust the speed of the bed. Furthermore, batterylife is extended due to the bed slowing down from gravity and frictionwhen the user removes his or her hands from the push handles or bed.Alternately, the automatic control may be responsive to other actuatinginput at the handle or at the headboard. For example, the handle orheadboard may include one or more heat sensors, which detect heat at thehandle or headboard, which generate actuating signals to the automaticcontrol. Alternately, one or more handles or the headboard may include aswitch, which when actuated generates the actuating input. Further, theautomatic control may be based on displacement, such as a proportionaldisplacement, of one or more of the handles.

III. Structural Informatics Systems

The hospital bed of the present invention further comprises structuralinformatics systems that enable the operation, control, monitoring, andevaluation, of the various electronic elements and conditions of thebed. The bed can comprise one or more of a plurality of electronicelements, for example, load sensors, tilt or angular sensors, linearsensors, temperature sensors, illumination sensors, humidity sensors,pressure sensors, electronic controls and keyboards, wiring actuatorsfor adjusting bed angles and the like, in addition to other electronicelements.

Sensor and Detector Subsystems

A hospital bed of the present invention can include one or more sensorsand detectors for sensing and detecting the status of structural orfunctional components of the bed as well as certain vital signs of asupported person. For example, sensors or detectors can be appropriatelydesigned load sensors, angular movement sensors, pressure sensors,temperature sensors or any other type of sensor or detector that wouldbe appropriate for integration into a hospital bed as would be readilyunderstood by a worker skilled in the art. Each of these sensors ordetectors can be configured to evaluate a desired piece of informationrelating to the supported person or the bed itself, for example theinformation can relate to the mass of the patient, the orientation ofthe bed in terms of position of the supported person or othercharacteristics.

In some embodiments of the present invention, there is provided a systemfor detecting the angular position of the supported person. The angulardata collected can be applied in a number of ways in the overalloperation of the bed, as will be discussed below. However, due to thedynamic nature of the bed, potential inaccuracies associated withmechanical sensors may arise. Gravitational accelerometers that rely onan inclinometry method to determine the angular position of a patient,can be used to improve accuracy. Although the accelerometers can providean effective way to measure the inclination in the patient's position,the resolution of the gravitational accelerometers is restricted to alimited range of inclination angles. The resolution of the angularposition of a patient can be improved by using dual axis (X-Y)accelerometers to sense the inclination angle with a higher degree ofaccuracy over a broader range of inclination. Advantageously, thegravitational accelerometers can be orientated in a variety of mountedangles, independent of any frame of reference. As a result, a particularaccelerometer can be positioned such that its effective resolutionspecifically targets the anticipated range of inclination for a givenapplication.

In one embodiment of the invention, the bed comprises a plurality ofgravitational accelerometers located in various parts of the apparatusto provide a more complete picture of the patient's position. In someinstances, the patient's angular location for a therapy may be importantin relation to the gravity. For example, gravitational accelerometerscan be located at the head section, Knee Gatch or seat section, footsection, elevation system and base frame. Output from the plurality ofaccelerometers can be compiled to provide a three-dimensional view ofthe patient's position. The angular inclination readings from the X-axischannel or the Y-axis channel of an accelerometer can be independentlyselected. Moreover, the sensed inclinations can be used to complementmeasurements from other sensors in the bed, such as load cells. Thus thefloor angular effect may be effectively removed form the load cellreading.

In another embodiment of the invention, monolithic gravitationalaccelerometers are employed to further reduce the inaccuraciesassociated with mechanical sensors. In other embodiments, various typesof sensors may be used such as angular solid state sensors or electronicangular sensors, wherein a change in angle of the sensor changes theimpedance of the sensor which is measured.

In a further embodiment, there is an analog system (such as apotentiometer), which outputs a PWM signal with a good S/N ratio. ThisPWM signal is sent to a microcontroller wherein the period of the signalis measured and the on-time of the signals. A ratio of these results isproportional to the sine of the angle. The cosine of this angle is tocalculate the desired angle. A microcontroller can also be used withreference to a look up table to determine the appropriate angle relatedto the collected data.

The positions of the angle sensors can be located anywhere on the bedand further comprise an integrated connection mechanism to enableattachment of the sensor to the desired location. For example, the anglesensors can be positioned at the: Fowler (head section), Knee Gatch(seat section/foot section), intermediate frame (to measure theTrendelenberg angle), elevation system at the head-end of the bed, baseof the bed, or elevation system at the foot-end of the bed.

Angle sensors can also be placed in other bed locations, for example,the side rails or the footboard control panel. In the latter, a sensordetermines if the angle of the control panel puts it outside of thefootprint of the bed, which could result in damage. Such an event maytrigger the non-disengagement of the braking system if requested.Sensors can also be coupled to bed accessories, for example sensors canbe coupled to an IV pole coupled to the bed, such as on an accessorysupport, to determine the amount of fluid left in the IV bag.

Angular Data

There are a plurality of potential uses for the angular data collectedby the structural informatics system of the present invention that canbe applied to the functioning of the bed and overall patient care. Forexample, if predetermined patient positions are directed by a healthcare provider, a sensor can provide the true value of the position ofthe lying surface and consequently of the patient who is lying thereon.In another embodiment, an angle sensor can also provide a means todetermine bed part interference. For example if a particular bed part isarticulated at a certain angle, another part may be unable to performits desired function. The detection of no change in an angle when anactuator is being operated to change the angle can indicate a blockagerelated to the actuator movement or an actuator malfunction. A sensortherefore provides a means for fault detection.

In other embodiments of the invention, the collection of angle changingdata can be used by the health care provider to evaluate the patient'sposition over time (for example over a period of 44 hours). A desiredpositional change of the patient, for example with the inclusion of atimer, can indicate when to change the patient's position. Positionalchanges may occur automatically however the patient's movement isusually strictly monitored by the health care provider.

The collection of angular data can also aid in the maintenance of thebed. In one embodiment, the angle of a particular bed section and theperiod of time that that particular position was held as such can bedetermined to avoid undesired stress levels on the bed. For example, bedmovement can be terminated based on measurements from a sensor, whereinonce a particular bed position is reached, the controller prohibitsfurther movement as it would result in undesired stress levels on thebed's components. In this way, especially when a particular positionresults in higher stresses on the lifting mechanisms and the bed'sstructure, maintenance of the bed can be facilitated. In a furtherembodiment of the invention, having a highly sensitive angle measurementsystem also enables the adjustment of a patient's angular position by asmall variation such as 1 or 2 degrees, which can result in a desiredchange in pressure points noticed by the patient with minimal patientmovement.

In addition to detecting angular changes relative to the length of thebed, other embodiments of the invention comprise sensors that areoptionally oriented within the bed frame or mattress to determinetorsional movement of the bed (rotation along the length of the bed).Such an angular sensor configuration can provide for rotational therapyof a patient. In other embodiments of the invention, angular sensors canalso be used to detect positions which are dangerous for a patient andtherefore the sensors can enable termination of bed movement if aparticular position is achieved. In another embodiment of the invention,the mattress could also be configured with an angular sensor for theFowler or head section of the mattress.

Calibration of the sensor is performed whenever a sensor is changed andcan be conducted periodically, such as once a year, in order to verifythe accuracy of the sensor. The calibration procedure can be bedspecific and is directly related to the number of angle sensors in thebed. For example, the calibration can be performed using four positionalorientations: Bed flat in low position, Bed flat in Trendelenbergposition, Bed flat in reverse Trendelenberg position, and Bed surface athighest location with foot at lowest, seat at highest and Fowler or headat highest. The angle is calculated using the angle sensor and also thetrue angle is measured in order to determine the desired calibration ofthe sensor. Since at least one sensor is positioned on the elevationsystem, as sections of the elevation system rotate, the height of thebed surface can be calculated.

In one embodiment of the invention, the sensors are intelligent sensors,for example, sensors containing embedded processing functionality thatprovide the computational resources to perform complex sensing andactuating tasks along with high level applications. As such, the sensorsenable the patient support apparatus of the present invention to performtasks such as its own diagnostic evaluation and its own calibration. Inanother embodiment of the invention, the sensors are connectable to asensor network. In a further embodiment of the invention, the sensorsare connectable to a wireless sensor network.

In one embodiment, angular data is used to monitor and, when applicable,adjust an operation of the elevation system 500. For example, asillustrated in the embodiments of FIGS. 17A to 23, the elevatingmechanism 500 may comprise a pair of lift arms 502 disposed between thebase frame 200 and the intermediate frame 400 and configured to beactuated by respective actuators 504 to selectively raise and lower eachend of the intermediate frame 400, either independently orsimultaneously, relative to the base frame 200. The respective actuators504, or other such drive mechanisms known in the art, may be capable ofoperating at variable speeds for selectively adjusting an elevation ofthe intermediate frame 400. In general, the respective drivemechanisms/actuators 504 may be configured to initially operate atrespective, substantially equal, maximum operating speeds. As theintermediate frame 400 is raised, at least one angle sensor locatedthereon or on another frame or structural module mounted thereon (e.g.sensor 622 mounted to the load frame in the illustrative embodiment ofFIG. 31) may be provided to determine an angle of inclination of theintermediate frame 400 (or load frame 600 in the illustrative embodimentof FIG. 33). A control module of the control system 1000 for selectivelycontrolling the elevation of the intermediate frame 400 can thus assessthis inclination during a change in elevation of the intermediate frame400 as compared to a starting angle of inclination thereof and adjustthe operating speed of one of the respective drive mechanisms/actuators504 to compensate for any undesired change in intermediate frameinclination.

In another example, angular data may be used to maintain an angle ofinclination of the intermediate frame 400, and of other frames and/orstructural modules mounted thereon, when this frame is subject to anuneven distribution of load. This load can optionally be detected andmonitored by load cells disposed between the intermediate frame 400 andthe deck support 700, for example, as provided by load cells 602illustratively depicted in FIGS. 26 and 31. In general, the controlsystem 1000 may be communicatively connected with one or moreinclinometers, as in sensor 622 of FIG. 31, as well as with therespective drive mechanisms/actuators 504 of the elevation system 500,the latter configured to selectively raise or lower each longitudinalend of the intermediate frame 400 relative to the base frame 200. In afirst step, the starting angle, generally the desired angle, is firstacquired by the control system 1000. The drive mechanisms/actuators 504may then be activated to change an elevation of the first and secondends of the intermediate frame 400 respectively associated therewith,each initially operating at substantially equivalent maximum speeds. Asthe intermediate frame 400 is raised or lowered, a current angle ofinclination of this frame may be monitored, for example via sensor 622disposed on the load frame 600. When the control system 1000 observesthat the current angle of inclination differs from the starting angle ofinclination (e.g. possibly within a given tolerance), the speed of oneof the drive mechanisms/actuators 504 may be adjusted to compensate forthis change of inclination. This procedure may be repeated andmaintained until a desired elevation is reached, at which point theelevations mechanism 500 is stopped.

Similar applications are disclosed in US Patent Application publicationNo. 2006/0021143 A1, the entire contents of which are incorporatedherein by reference. The person skilled in the art will appreciate thatthe features disclosed in the above Application may also be applicablein the present context, without departing from the general scope andnature of the present disclosure.

The person of skill in the art will appreciate that other such controlsubsystems may be implemented using angular data acquired by the one ormore inclinometers disposed on or within the structural elements of thebed 100, in conjunction with the various actuation controls discussedabove, without departing from the general scope and nature of thepresent disclosure.

Diagnostic and Control Subsystem

The hospital bed of the present invention can comprise a diagnostic andcontrol system that enables the specific control of each of theelectronic elements of the bed, discussed above, for desired operationthereof and monitoring of the operating conditions of these electronicelements and additional bed conditions. The diagnostic and controlsystem further enables the evaluation and determination of the existenceof one or more faults relating to the operation of the bed. For example,the existence of a fault can be conveyed to an operator in the form ofan error message. The diagnostic and control system can subsequentlyevaluate the detected fault and can determine, for example, a causethereof and a potential remedy. In this manner the diagnostic andcontrol system can provide the evaluation of the detected fault andsubsequently provide the operator or technician with a remedy for thedetected fault, thereby reducing the downtime of a bed that comprisesthe diagnostic and control system.

Control Subsystem

The diagnostic and control system can comprise a single monolithicsubsystem or one or more modular subsystems enabling the control,monitoring, and, if required, calibration of the electronic componentsof the bed. In this manner the functionality of each of the electroniccomponents, for example load sensors, temperature sensors, tilt sensors,actuator position sensors, actuators and the like can be evaluated andassessed for functionality within a desired set of parameters.

The diagnostic and control system can further monitor or query thefunctionality or status of the electronic elements, including forexample, actuators, load sensors and the like. The system can monitorthe current status of the operational parameters of these electronicelements and cross-reference the collected data with a set of standardoperational characteristics. In this manner the system can be providedwith a means for detection of a potential fault or error when a specificelectronic element is not operating within a desired and/orpredetermined range. For example, if a load sensor is being monitoredand an extraneous load reading is detected, the system can re-query theload sensor to evaluate if it was merely an inaccurate reading or if apotential problem exists. This extraneous reading may be for example areading that may be outside of normal operating conditions of the loadsensor or may be evaluated as extraneous upon comparison with other loadsensors in the vicinity, for example. Each of the electronic elementsassociated with the bed can be monitored in this manner as would bereadily understood by a worker skilled in the art.

The diagnostic and control system can perform the monitoring of the bedsystem components in a continuous manner, periodic manner or on-demandmanner. The frequency of the monitoring of these components can bedependent on the electronic element being monitored. For example, theformat of the monitoring can be dependent on the level of computationthat is required to determine if a component is operating within desiredand/or predetermined parameters. Constant monitoring may includequerying the sensors for current readings for comparison withoperational parameters. Periodic monitoring may be performed whenevaluation of the orientation and angular position of the bed frame isdesired and on-demand monitoring may be performed on the diagnostic andcontrol system itself wherein monitoring thereof would typicallycomprise a more extensive computation of current status.

In one embodiment of the present invention, the diagnostic and controlsystem initializes or calibrates the operation of each of the electronicelements, for example actuators, load sensors and tilt sensors, in orderthat these electronic elements can provide the desired level of accuracyand desired functionality to the bed. For example, calibration of a loadsensor may be performed when a lying surface is positioned on the bedand the load sensor can be zeroed under this condition. Furthermore, oneor more of the actuators and tilt sensors can be calibrated or zeroedwhen a bed is in a known orientation, for example linearly flat in ahorizontal orientation.

In one embodiment of the present invention, the diagnostic and controlsystem, while providing control of the functionality of the bed, canadditionally ensure that a procedure requested by a user is bothpossible and safe to be performed. In this scenario the diagnostic andcontrol system can evaluate the current status of the bed, andsubsequently determine if the selected function is possible. For exampleif an operator requests the elevation of the head-end of the bed, thesystem can determine if the head-end can be elevated, and if thisprocedure is possible, subsequently perform the desired function. If,for example, the head-end was fully raised, and the function wasperformed regardless, the actuator performing the requested function maybe unnecessarily damaged due to overloading or over-extension, forexample. This evaluation of the requested function can additionally bedetermined based on a current treatment being performed on a patient.For example, if a patient is to be oriented in a particular position,the diagnostic and control system can be configured to not allow anyadjustment of the bed system until this particular position can bechanged according to treatment procedures or requirements.

In one embodiment of the present invention, the diagnostic and controlsystem can be designed using an interface-controller-model architecture.The interface can provide user access to functions of the bed, as wellas a query or notification system that can provide access to bedfunctionality, or notify monitoring personnel of important statusinformation about parameters of bed functionality in addition to certainvital information about the supported person. The model can provide anabstract description of the bed's operational parameters, for exampledesired operating conditions in the form of a virtual machine, data setor database. The interface and controller can also read information fromthe model and based on current detected status of the electronicelements associated with the bed, can determine if the bed is performingwithin desired parameters. For example, a representational model for acollection of load sensors can be provided which can provide operationalparameters for the load sensors that can additionally be representativeof the configuration of a load sensor web, thereby providing a means forevaluating the operational characteristics of the load sensors duringoperation.

In one embodiment of the present invention, the diagnostic and controlsystem can include one or more monitoring sensors that can provide ameans for independently monitoring the functionality of one or more ofthe functions of the bed. For example, a monitoring sensor can beassociated with an actuator, wherein this monitoring sensor can be atemperature sensor that may enable the detection of overloading oroveruse of an actuator due to an excessive temperature reading. Thediagnostic and control system may optionally comprise redundant sensorsfor example, which may be activated upon detection of extraneousreadings for a typically used sensor. This form of redundancy canadditionally provide a means for evaluating the operationalcharacteristics of the electronic elements associated with the bed.

In one embodiment, an interface associated with the diagnostic andcontrol system can provide one or more different classes offunctionalities to one or more different categories of users. Forexample functionalities can be categorized into functions accessible toa supported person, functions accessible to a monitoring person, andfunctions accessible to maintenance personnel for accessing diagnosticfunctionality. Consequently, there can be user interface subsystems thatare available and intended for use by a specific user group. Functionsof the patient support can also be grouped according to a person'sphysical accessibility to the bed and can be accessible on-site orremotely or both. As a result, the control system can interact with twoor more physical tangible human-machine interface subsystems such as forexample a console embedded in the bed. Another important aspect of thepresent invention is the ability to connect to the bed's controlsubsystem and diagnostic subsystem and transfer information therefrom orinstructions thereto via a suitable number of user interface subsystems,for example communication systems using wired or wireless devices.Therefore, the diagnostic and control system according to one embodimentof the present invention provides the ability to obtain diagnosticinformation from the bed via wireless devices or by connecting acomputer or other wired communication device to the bed. This providesan end user or a technician a means to access constructive informationabout the bed for any repairs or maintenance that could be required. Ina similar fashion, the monitoring personnel or health care provider canhave access to information about the supported person without being inclose proximity to the bed incorporating the diagnosis and controlsystem.

Upon the detection of a fault or error, the diagnostic and controlsystem can activate an alarm setting that can be a visual, audible orother form of fault indication. For example, the interface associatedwith the bed can have an error message displayed thereon. In oneembodiment, this error message can provide a means for a technician toevaluate and correct the identified fault.

In one embodiment of the present invention, upon detection of a systemfault during the monitoring of the functionality of the bed, thediagnostic and control system can initiate a full diagnostic subsystemwhich can perform a more complete system diagnostic evaluation and, inturn, evaluate and identify one or more sources of the detected systemfault.

In one embodiment of the present invention, the diagnostic and controlsystem can collect specific information relating to the current statusof particular components of the bed that are directly related to thedetected fault, for example one or more sensor readings or the like, forsubsequent use by the diagnostic subsystem for analysis of this fault.

Diagnostic Subsystem

The diagnostic and control system of the present invention comprises adiagnostic subsystem that can collect and evaluate the collectedinformation relating to an identified fault and perform an analysisthereof in order to determine a source of such fault and a potentialremedy to the detected fault. The diagnostic subsystem can indicatemalfunctions of the bed's control system which can be due to a number ofreasons such as for example an actuator break-down, an unacceptabledeviation between a parameter of the bed and the control system'sparameter's desired value as, for example, caused by overload or lack ofcalibration of an actuator, or any other condition of the bed's controlsystem. A diagnostic program may be applied in order to make adistinction between any critical or non-critical function of the bed'scontrol system when diagnosing a malfunction.

In one embodiment the diagnostic subsystem can also record a number ofevents including system data and user commands into one or more logrecords, for example one or more files in an embedded or a remotecontroller or computer system. Furthermore, essential informationregarding any form of treatment administered to the supported person canbe securely recorded which could be used in the future. The log recordscan also contain information from other subsystems of the bed.Information in the log records can be categorized; time stamped, and cancontain human or machine-readable data describing the event. The datacan be encoded, encrypted or clear text messages. Each subsystem canhave its own logging mechanism for logging events specific to thatsubsystem, accessible only through an interface of the subsystem oraccessible through interaction with a central controller. Events can becategorized into groups according to a severity or other schemes and,depending on the categorization, include varying degrees of detailedinformation relevant to a particular category.

In one embodiment of the present invention, the diagnostic and controlsystem has a movement counting device (data logger) which is used toproduce a diagnostic that can be used to improve the design of thesystem for specific uses or to perform preventive maintenance on thesystem. For example, it will be possible for an establishment utilizingsuch a diagnostic and control system, to use the data logger in order todetermine the different ways in which the bed is being manipulated andtherefore provide information in a very constructive manner for anyfuture designs. The information gathered by the data logger could alsoused in preventive maintenance such that more attention is given to anyparts of the bed that is involved in more motion or manipulation.

In one embodiment the diagnostic subsystem can analyze the detectedinformation relating to the functionality of the bed associated with thedetected fault, and subsequently evaluate one or more indicators thatcan be compared with known indicators of known problems relating to bedfunctionality. In this manner, based on a comparison with the indicatorsof known problems, the diagnostic subsystem can determine the specificproblem. Once a specific problem has been identified, a possiblecorresponding remedy for this problem can be identified, therebyproviding a means for the remediation of the identified problem. Thecorrelation between a calculated indicator defined by informationrelating to the present status of the bed system may not precisely matchan indicator of a known problem. In this instance a probability ofcorrelation between the evaluated indicator and the known indicator canbe determined thereby providing a means for assigning a confidencefactor with the identified problem.

In one embodiment of the present invention, the diagnostic subsystem canevaluate the identified fault through the analysis of previouslydetected readings, thereby providing for a correlation between thecurrent readings at fault detection and previous readings. This mannerof analysis may provide a means for identifying a malfunctioningcomponent, for example a sensor through the correlation with previouslydetected values.

In one embodiment of the present invention, the diagnostic subsystem canbe directly integrated into the bed. Optionally, the diagnosticsubsystem can be electronically coupled to the bed upon the issuance ofan error notification. Moreover, the bed system architecture cancomprise a diagnostic interface providing access to the bed system suchthat a diagnostic subsystem can be separated or detached from thephysical bed and provide the same set, a subset or superset ofdiagnostic tools than an integrated diagnostic subsystem.

In one embodiment of the present invention, the diagnostic and controlsystem comprises a communication system that can provide a means fortransmitting information relating to the evaluated functionality of thebed to another location. In this embodiment, the communication systemcan enable wired or wireless communication. For example, this form ofconnectivity of the bed may enable the remote monitoring of bedfunctionality at a location removed from the location of the bed. Forexample, in a hospital setting, this remote monitoring can be performedat a nursing station or optionally can be provided at a remote locationremoved from the hospital. The communication system can enable thetransmission of monitoring and diagnostic results to a technician foranalysis, for example if a more detailed diagnostic analysis of the bedis required in order to determine the source of the indicated error.This can provide a means for a detailed diagnostic to be performed andan appropriate remedy identified prior to the dispatching of atechnician to the bed site. In this manner, time may be saved as thetechnician may be dispatched with appropriate replacement parts, therebyreducing the downtime of the bed.

The functionality of the diagnostic and control system according to thepresent invention can be provided by any number of computing devices,for example one or more microprocessors, one or more controllers or oneor more computer systems that can be integrated into the bed itself inorder to provide the desired computational functionality.

In one embodiment of the present invention, the diagnostic subsystem canbe configured for coupling to the bed to subsequently provide thediagnostic capabilities. It would be readily understood how to couplethe diagnostic and control system to the one or more electronic elementsin order to data transfer therebetween, for example this connection canbe a wired or wireless connection.

Scale Subsystem (Patient Surveillance and Monitoring Subsystem)

Sensed inclinations can be used to complement other measurements fromother sensors in the bed. In some embodiments of the invention, there isprovided a bed monitoring system, which comprises a scale and bed-exitsystem that can be based on a load cell measurement scheme including theevaluation of the patient's center of gravity. In this way, thepatient's weight, as well as movement, can be continuously monitored.

Load Cell Measuring Scheme to Reduce Patient Motion on the ScaleMeasurement

A patient weight measuring system in a bed is provided to reliablyquantify the weight of a patient independent of the patient's movementsin the bed. The patient weight measuring system utilizes a system ofsensors, which provide readings to a data acquisition controller. Theweight measurements are processed and displayed, such as on an interfaceto indicate the patient's weight. Because of the physicalcharacteristics of the bed, stable readings of the patient's weightduring patient movements are obtained when the patient weight measuringsystem compensates for certain fluctuations in sensor readings whichnaturally occur during patient movement. The system models the physicalcharacteristics of the bed and it embeds a compensation means forcompensating sensor reading fluctuations, for example by time frequencyfiltering of sensor readings or by means of other data processingalgorithms. The compensation means can process and provide a meaningfulfigure of the patient's weight, which does not fluctuate during patientmovement conditions. The processing system may utilize a time averagingalgorithm that can average fluctuating load cell readings to meet thestable patient weight reading requirement. Such an embedded or remoteprocessing system can be manually or automatically calibrated.

Patient Movement Monitoring System

A patient movement monitoring system is also provided to detect andquantify patient movement as well as provide an indication when certainpatient movement or lack thereof is detected. For example, an alarm maysound when movement of the patient exceeds predetermined spatial limits.

The movement monitoring system can be based on a load cell measuringscheme that can trigger an alarm if patient movement (e.g., relative toa predefined perimeter within the bed surface area) occurs or exceeds apredetermined threshold. Moreover, patient movement that isperpendicular to the bed's surface or vertical may also be detected andmonitored. Parameters such as frequency and amplitude of patientmovement may be monitored to provide an indication of irregular orabnormal patient movement. Such information may be used to trigger analarm under lack or excess of patient movement which may indicatecertain patient conditions. The monitoring system requires a suitablealgorithm for the processing system to analyze patient movement. Thealgorithm may require considerable amounts of computational powerdepending on the complexity of the information required. In oneembodiment, the system provides a means for reinitializing after eachnew position of the patient. In another embodiment, the system providesthe time between the patient's movements to be preset in the program orcan be programmed by the operator. This information may be displayed,for example, graphically or may be displayed by an indicator, such as alight, for example.

Scale and Bed Exit Information Available at Nurse Station and ThroughExternal Port

The bed monitoring system, which can comprise a scale and bed-exitsystem, can provide information on the patient's weight, patient's bedlocation and other patient information, to a user such as a nurse orsurveillance staff at a monitoring station. In particular, the positionof the patient can be graphically displayed at a remote monitoringstation wherein the position can be displayed in a color-coded positiondiagram. In one embodiment, based on the patient's bed position, thelikelihood of a patient exiting the bed can be determined and anappropriate alarm can be initiated if bed exiting has occurred or islikely to occur. In a further embodiment, based on the ongoingevaluation of the patient's position, movement of the patient can beevaluated, thereby providing a means for issuing an alarm due to patientactivity, for example when a patient in ICU is awakening, or patientinactivity, for example when a patient's physical state is degrading.

Depending on the design or architecture of the bed monitoring system,embedded or remote processing capabilities may be required which canhave influence on the bed communication interface system (e.g.: anexternal port) by which the bed system can communicate information tothe monitoring station.

FIG. 62 illustrates an embodiment of a load cell system that may be usedfor monitoring movement of a supported person. The system can beintegrated into the bed or can be part of a person support element suchas a mattress. In addition, the load cell system can comprise a numberof load cells or load sensors for example a load cell which can beembedded in the bed proximally positioned at each of a supportedperson's limbs and optionally at the center of the bed. The load cellsystem also can be comprised of a mesh of load cells for example. Thesignals from the load cells can be monitored and processed by aprocessing unit in the load cell system or a central processing unitcapable of monitoring, processing, and controlling signals from thebed's subsystems. Instead of forming part of a support element such as alying surface the load cell system can also be integrated into thesurface of the bed for supporting the support element. The load cellsystem can provide a measure for the pressure, weight, or mass load of acertain load cell, for example foot left or right load cell values andhead left or right load cell values and additional information about thelocation of the center of gravity.

In one embodiment the diagnostic and control system can comprise anadditional scale subsystem providing a calibration process forcalibrating the scale subsystem to provide accurate reading of asupported person's weight and subsequently to calibrate a motiondetection system for monitoring movement of a supported person. It maybe necessary to calibrate the load cell electronics in order to providea match of the sensor signals with the scale subsystem electronics.

The scale subsystem can connect to a number of load sensors. The numberof load sensors can be different from the ones illustrated. For example,four load sensors which are capable of sensing pressure and can becalibrated to provide a measure of force or weight applied to eachsensor are attached to the scale subsystem control interface. The scalesubsystem controller can process signals incoming from the load cellsand can be used to detect the status of a supported person. The scalecontrol subsystem can be configured to provide a messaging signal or toalert monitoring personnel through an external alarm system interfacefor example. If each load cell is properly calibrated, the scale controlsubsystem can also provide a measure of the weight of a supportedperson. The information can be utilized to determine a person's mass orweight or the respective mass or weight and can also be used to recordthis information in another subsystem of the bed that may be desired forpatient monitoring for example.

In one embodiment, the scale subsystem may require occasionalcalibration depending on the nature of the chosen sensor technology.Access to the scale subsystem for calibration, monitoring or diagnosticpurposes may be possible through the user interface.

It is understood that any kind of diagnostic procedure also includesinspection of the corresponding component and that each component mayprovide a hardware interface for connection to a special purposediagnostic device for diagnosing the component.

Actuator/Motor Control System

As discussed earlier, the bed of the present invention can be configuredinto various positions by orienting the head, seat, and foot sections ofthe bed into desired positions. The positioning of the various sectionsof the bed can be controlled by an actuator/motor control system. FIG.61 schematically illustrates an embodiment of the actuator controlsystem with a number of attached actuators and sensors, such as limitswitches, which will be more fully described below. It is understoodthat, depending on the functionality of the bed, there can be differentnumbers of actuators and sensors than illustrated. In this embodimentthe surface of the bed can be shaped by orienting a head, seat, and afoot section where the support surface for a supported person isintended to fold and provide an adjustable angle between the upper bodyand the seat as well as under the knee between the seat and the lowerleg. The head actuator can position the end of the head section, and thethigh actuator can position the knee section of the bed surface relativeto an even support structure. The HI-LO head actuator can position thehead-end of the even support structure relative to the frame of the bedwhich is in contact with the floor. The HI-LO foot actuator can positionthe foot-end of the even support structure relative to the frame of thebed, for example. The two HI-LO actuators can pivot the support surfacehorizontally whereas the head and the seat or thigh actuator can shapethe support surface by pivotally adjusting sections of the bed surface.

In one embodiment, the actuator control system is connected to a numberof limit switch and/or angle sensors which ensures that the actuators donot move or position parts beyond predetermined limit angles ordistances. When a part or section of the bed reaches a predeterminedlimit position while moving, the actuator control system can receive astatus change signal via one or more limit sensor signals and/or anglesensor signals and can interrupt the respective movement. The actuatorcontrol system can have a safety control feature that does not allow anyfurther continued movement in that same direction or orientation unlessthe limit condition indicated by the sensor system is resolved. Providedthat no movement of other degrees of freedom of the bed takes place thelimit condition typically can be resolved by reversing the originalmovement. For example, limits switches may be used to prevent, forexample, the foot-end section of the deck from bumping into, forexample, an IV pole.

As discussed previously, each component of the actuator control systemincluding the actuators and sensors can provide diagnostic features or adiagnostic mode. The diagnostic features also can include a separateredundant diagnosis sensor subsystem for monitoring the state of therespective device or component for example a temperature sensor or aredundant parallel or serial sensor limit switch system to enhance thereliability of the positioning system. An important aspect of thediagnostic subsystem that is relevant to the actuator control system canregard the accurate calibration of sensors providing actuator positioninformation. The actuator control system interprets actuator positionsensor signals to be accurate representations, encoded in form of asuitable signal, of the real position of a respective part or section ofthe bed. The actuator control system may fail to execute a given commandwhen the real position deviates from the actuator control system'sperceived position as provided by or derived from an actuator signal. Insuch a case the diagnostic system can provide functionality to helpavoid or diagnose a malfunction which can reach from functionalitiessuch as automatic recalibration to alerting or messaging.

System Architecture

FIG. 8A illustrates a schematic diagram of the system architecture ofthe control system with a diagnostic system of the present invention.The architecture can be divided into a number of user interface andcontrol subsystem components. The system architecture comprises a poweror AC control system for supplying electrical power, an actuator ormotor control subsystem providing ability for positioning and orientingparts of the bed, a number of sensor and detector subsystems for sensingand detecting the state of parts of the bed, and a diagnostic subsystemas indicated. The diagnostic subsystem can interact with the sensor anddetector subsystem or it can have its own redundant sensor and detectorsystem. The user interface subsystem can comprise a number of controlconsoles comprising indication or display systems. The display systemscan have a touch screen or a regular display with separate useractuatable devices, such as buttons. The sensor system can comprise ascale subsystem including a load cell system. The system architecturecan further comprise a room or other interface for communicatinginformation to and from the bed and a remote user interface system.

In one embodiment the bed system architecture further comprises a modelsubsystem or virtual state machine for representation of the state ofthe bed components for interaction with the controller and the userinterface under operating conditions. Each control subsystem cancomprise its own model and independent processor or the model of thesubsystem can be integrated in a central program controlled by a centralprocessing unit controlling the bed system.

In one embodiment the architecture may include a diagnostic subsystemfor monitoring or querying the functionality or status of the bedcomponents. The diagnostic subsystem can be separate from or simply anadditional component of the one or more control subsystems. Thediagnostic subsystem can monitor some or all of the bed actuators andcan utilize an operatively required and already present sensor system orthe diagnostic subsystem can have its own redundant sensor system forimproved reliability of the bed control system. The diagnostic systemmay monitor the bed components on a continuous basis during the bed'snormal or intended operation or it may be activated only when requiredto perform certain maintenance procedures. None, some or all of thefunctions intended for use during normal operation of the bed may beavailable during some or all of the diagnostic maintenance procedures.In addition, it may be safe for a person to remain in the bed duringnone, some or all of the diagnostic maintenance procedures.

In one embodiment the diagnostic subsystem can comprise sensors for thepurpose of self-diagnosis of the bed control system sensing the statusof actuating components for example. Such sensors may not be required tosense the status of the bed per se but rather provide access toimportant status information of the control system. Examples can includethe temperature of actuator components or controller hardware.

In one embodiment of the present invention, the diagnostic subsystem canpassively alert users through messaging systems, for example errormessages displayed on the display system. The diagnostic subsystem mayalso provide procedures to actively query internal status information ofthe bed system not intended for use during normal operation. Examples ofinternal status information can include any kind of readings fromsensors or results from self-diagnostic modes of employed digitaldevices. This information can be important, for example, whencalibrating actuators and their respective motion sensor system toaccurately scale sensor readings to provide positioning information thatcorresponds with the true physical position of the respective bedcomponent. Other examples for internal status information include powersupply voltages or current readings.

In one embodiment the diagnostic subsystem can also include a debug modepermitting the step-by-step execution of commands or procedures of themicrocontroller or processing unit. For example, the diagnosticsubsystem could be accessed via a general purpose computer for extensivedebugging of such subsystem.

The communication between different components within the bed controland diagnostic system is achieved through network communication betweencomponents such as CAN-Open for example. This protocol utilizes thebroadcast of information to the different electronic components (ormodule) within the bed. Information regarding any commands requested bythe end user is thus transferred to every single electronic componentwithin the bed and thereafter, action is taken by the component (ormodule) which is concerned by the information that has just beenbroadcast. Alternatively, the communication between different componentswithin the bed control and diagnostic system can be achieved by apeer-to-peer network communication system or any other networkcommunication protocol that would be known to a worker skilled in theart.

IV. User-bed Communication Interfaces

The control interface allows for various adjustments to be made to thebed, such as adjustment of the relative position of the individual partsof the bed to position the patient on the bed, adjustment of the bedlength and adjustment of the vertical position of the bed. As well, thecontrol interface also allows for monitoring and control of variousother functions, such as the communication capabilities of the bed withother apparatuses (e.g., vital care analytical apparatuses, heartmonitoring apparatuses, etc.), the monitoring of the status of the bed,and the monitoring of the status of the patient, for example.

The bed of the present invention can comprise one or more controlinterfaces at various locations to facilitate operator use.

Control Apparatus

The bed of the present invention comprises a control apparatus that canbe ergonomically and movably connected to facilitate operator use. Thecontrol apparatus comprises a control module which is operativelycoupled to the bed and can provide a means for controlling the pluralityof bed functions. The control module may be located in control console976 and as previously described in reference to FIGS. 51A and 51Badapted for connection and is movably connected to the bed by a couplingdevice, such as described in copending application Ser. No. 11/588,726,filed Oct. 27, 2006, entitled Ergonomic Control Apparatus for a PatentSupport Apparatus, which is assigned to Stryker Canadian Management ofCanada and which is incorporated by reference herein in its entirety.The coupling device enables the relative movement of the control console976 and as such the control module relative to the bed. In this manneraccess to the control module, and therefore to the functionality of thebed, can be provided independent of the configuration of the bed at anygiven time.

In one embodiment as illustrated in FIG. 51A, the control module islocated at the foot-end of the bed, coupled to the footboard by console976. The control console 976 is operatively and pivotally connected tothe footboard and can pivot on at least one axis with an angle from 0 to360 degrees so that the control console 976 may be angled to suit thenurse attendant or the like. As illustrated in FIG. 51B, the pivotalaxis is shown to be substantially horizontally perpendicular to thelength of the bed. In the stored position, as shown in FIG. 51A, userinterface 978 of the control console is facing the exterior of the bed.

It would be readily understood that the illustrated embodiments can bemodified in a manner in which the control apparatus would be located ateither the head-end or foot-end of the bed, wherein a control module maybe embedded in either the headboard or footboard or both or in otherlocations in the bed.

In another embodiment, the control module can be operatively connectedto the deck support or the intermediate frame and positioned at anydesired location along the length of the bed. In this embodiment, thecontrol module is movably coupled to a coupling device, which isfastened to the deck support or intermediate frame. In theseembodiments, the coupling device can be configured as an extension armwhich can provide a desired level of movement of the control modulerelative to the deck support or the intermediate frame.

Housing

The housing of the control apparatus is configured to physically housethe control module. The shape and construction of the housing is notrestricted to a particular design but can rather be dependent on theattachment location, for example the footboard, headboard, deck support,intermediate frame, etc. The configuration of the housing can also bebased upon the type of coupling device used for operatively connectingthe housing to the bed. In addition the housing can be specificallydesigned for a desired level of impact resistance or strength, forexample. As such, variations in the shape and construction of thehousing which provide the desired functionality described herein may bedesign choices for both functionality, position and aesthetics.

The housing may have affixed thereto electronic cards, user actuatabledevices, such as buttons, and other controls necessary to allow for thecontrol of the operation of the features of the bed. The supports forthese electronic cards can be made of transparent or translucentmaterial to diffuse the light uniformly on the whole surface underneaththe user interface. The transparent or translucent supports can beaffixed from the outside of the module or housing. It may not benecessary to open the main control module to access the electroniccomponents, which minimise the assembly time of the control apparatus.

In one embodiment of the invention, the user interface can be mounted ona metal plate through magnetic force. The control module can be equippedwith a magnetised surface to receive the metal-based interface. The userinterfaces can cover all of the joints between these components toeliminate cleaning and contamination problems caused at the physicaljoints between the various sub-components. These magnetised interfacescan be advantageous as they do not require adhesives to assemble all thecomponents of the control module. They can further provide thepossibility for the patient or the operator to quickly change theoptions of the control module without having to replace the interfacewhich remains sealed and easy to clean.

Coupling device

The coupling device of the control apparatus provides a connectionbetween the housing and the bed. The coupling device can be configuredin a plurality of different configurations in order to provide movementof the housing in one or more different planes.

The coupling device can be for example, without any limitations, asocket-type connection which may enable three dimensional movement, arotational pivot, railings, and several operatively coupled rotationalpivots. The coupling device can also be configured as one or morecoupled link arms or flexible tubing. The coupling device can furthercomprise a combination of some of these elements among themselves orwith an articulated support arm or a fixed support arm, for example.

In one embodiment, the control apparatus comprises a stopping mechanismpositioned at intermediary angles between 0 and 360 degrees. Thisstopping mechanism can be either mechanical, electrical, hydraulic ormagnetic. In one embodiment a mechanical stopping mechanism is aratchet-type system. Alternately a frictional force may be used to bringthe control module to a static stop position. For example this stoppingmechanism can be configured using dampening grease, friction discs andsprings or a Stabilus Hydro-Lift®-type cylinder. The Hydro-Lift®-typecylinder uses a gas spring which allows variable positioning of theelement to which it is attached for example, the housing. Thearticulated support arm or fixed support arm can be adjusted by applyinga defined manual force and subsequently locked in the new restingposition. An advantage of integrating a Hydro-Lift®-type cylinder intothe coupling device is that this cylinder does not require an actuationmechanism for adjustment.

In one embodiment, the control module can also comprise a motor thatallows it to maintain a predetermined angle or position relative to thefloor regardless of the angle of the intermediate frame, deck support,footboard or headboard relative to the floor. The operator can adjust itmanually and then the control module can register the desired positionin order to keep it constant until the next change. The operator canalso adjust the angle of the motorised control module by using variouscontrols on the user interface.

In another embodiment, the control module can pivot on three axes,allowing three-dimensional movement. The control module is connected tothe bed though a coupling device. The wire linking the control module tothe bed can pass though the coupling device thereby not limiting themovement of the control module.

In one embodiment, the control module via the housing can be linked tothe bed by an articulated support arm or fixed extension arm. Such armscan be coupled to the intermediate frame or the foot-end frame to ensureit does not move if the lying surface is moved, for example throughmovement of the deck support. The arm can also be connected to the decksupport, for example at the head, seat or foot sections.

In one embodiment, the support arm can be removable from the bed,thereby allowing for versatility in the positioning of the controlmodule connected to the support arm via the housing. The receptorsenabling this movability of the support arm can comprise adapters forthe mechanical, electrical and electronic hook-ups required for thecontrol apparatus. These receptors can move to accommodate the needs ofthe health care provider, for example. In one embodiment, the supportarm may be coupled to the base frame of the bed.

In another embodiment, the control module is capable of sliding onstraight or curved rails. Non-parallel rails provide various controlangles depending on the relative position on the rails. A rail mechanismbetween the housing and a footboard of the bed is provided. The railmechanism comprises a pair of rails disposed on each side of theembedded cavity. Each rail can comprise a single groove pattern toreceive and guide one or more protrusions extending outwardly from eachside of the housing of the control module. The groove pattern on oneside mirrors the groove pattern on the other side and the protrusionsare located on corresponding locations on each side of the housing ofthe control module. In one embodiment, bearings can be used between theprotrusions and their corresponding groove patterns. The bearings canhelp reduce the frictional forces and thereby reduce wear of theprotrusions and their corresponding groove patterns while also reducinghigh contact stresses and facilitating movements from one position toanother.

In one embodiment, the coupling device can have features where thecontrolled movement of the housing relative to the movement of the bedis monitored by the control module and can be adjusted, in real-time oron command, in order to maintain a predetermined accessibility andvisibility to the control module by a healthcare provider. To achievethis, the coupling device can have a motorised component operativelyconnected to the housing and the control module can comprise apositioning sensor.

Control Module

The control module is operatively coupled to the bed, as describedabove, and can provide a means for controlling the plurality of bedfunctions.

The power for the control module can be provided by the bed or fromanother power source. If it is provided by the bed, it can be from analternating current or direct current. If it comes from outside of thebed, it can come from another medical apparatus having an auxiliaryoutlet or a battery pack (conventional or rechargeable), or directlyfrom a power source such as a power outlet. The power source can also bea photoelectric cell to keep the memory and the processors' power or ahigh or low frequency radiation energy. A further possible source ofpower for the control module is through an electromechanical settingthat will enable any mechanical motion to be used to generate current(electricity) that will, in turn, be used to recharge a battery whichcould be used to drive the control module. The electromechanical settingcan be as simple as a coil with a magnet or as complex as Piezo™ sensors(generators) which convert mechanical energy into electrical energy.Depending on the other source(s) used to power a particular bed, simplerAC (alternating current) electromechanical generators, known asalternators, or DC electromechanical generators can be used.

The control module is linked to a bed network, which can be of any kindknown in the art such as serial communication networks, CAN-basednetworks, Echelon™-based networks, peer-to-peer networks, etc. Thesetypes of networks do not represent limitations, as any type of knowncommunication network can be used without departing from the presentinvention. The control module can also be wireless, based on varioustypes of wireless communications networks such as, without limitations,RF (Radio Frequency field propagation) communications, Bluetooth®communications, Infra-red communications and ultrasound communications.

In one embodiment of the invention, the control module further comprisessecurity features to ensure that only authorized personnel access thecontrol module and thereby prevent misuse of the control module. Forexample proximity sensors can be included and can be in the form of apassive or an active RFID (Radio Frequency Identification) that signalsthe control module to deactivate and/or activate, based on presetoperator proximity readings, for example. In another embodiment, thecontrol module comprises a digital recognition system that positivelyidentifies only pre-authorized individuals to operate the controlmodule. Positive identification can be based on a variety of knownfeatures, for example fingerprints, an iris, or vein patterns, forexample in a hand.

As discussed earlier, it is an aspect of the invention that the controlmodule can communicate with apparatuses other than the bed. The controlmodule can have an antenna to communicate with and control functions ofthe other apparatuses through wireless communication or through wiredcommunication. As well, the control module can also communicate withother departments within the facility. For example, the control modulecan communicate with the radiography department to display the patient'sradiography results and the notes from his or her medical file from thisdepartment.

In another aspect of the invention, the control module can also comprisea camera and a speaker and a microphone. As it can be oriented in alldirections, it provides a continuous visual communication between thepatient and the health care provider. It can also be used forcommunication from one health care provider to another, whether thelatter is at a guard station, in another department, in front of anotherbed with similar equipment or even outside the facility where thecontrol module is located.

LCD Panel/Touch Screen

The control apparatus includes a console interface or LCD panel with atouch screen, at least one processor, software and programmable or flashmemory. In addition to providing the necessary algorithms to controland/or monitor the functions of the apparatus, the software provides agraphical user interface (GUI) to organize the multitude of functions ofthe apparatus. The GUI can display a set of symbols such as “icons” andbuttons in any arrangement for a particular function, for example, bedmotion. If another function is desired, the GUI can display another setof icons and buttons for that particular function.

The GUI can be configured such that the operation of each function iseasy to understand for an attendant who may be unfamiliar with all ofthe functions of the apparatus. Examples of functions that can beoperated or monitored from the LCD panel are: apparatus motion, mattressair pressure, patient motion, patient biometrics, scale, bed security,alerts, exit and event log/history, help screens, diagnostics, roomlights or doors/windows, motion sensors, etc. The actual screen displaysand menus of the touch screen for a particular bed will be determined bythe functions of the bed and the needs of the operator.

In addition, the control apparatus may include a display that provides astatus of the bed and displays data, for example in text format or thelike, about the bed status collected in the data logger of thediagnostic system. For example, the status of bed sensors, software, andcontrol output may be displayed. With this information, a maintenanceperson may diagnose the bed without needing special tools to removecovers or bed parts. This diagnostic tool, as noted, may be located atthe bed, for example at a separate display or at the main controlinterface. Further, the diagnostic information can be transmitted by thebed network to a dedicated external interface, such as an externalcomputer, or transmitted to a remote link via, for example, a modem,Ethernet, a wireless network, such as an RF network or the like.Further, this interface may be used to update the software.

For example, one embodiment of the invention comprising the followingcomponents and indicators:

-   -   A Touch Screen Display    -   B Bed Exit Detection Interface    -   C Mattress Interface    -   D Information Interface    -   E Modification of Intensity of Backlighting    -   F Lock Out System Interface    -   G System Message Indicator    -   H Indicator for detection of BED EXIT ON/OFF    -   I Weighing Scale Interface    -   J Motion Interface    -   K Brake Activation Indicator    -   L CPR Activation    -   M Steer Activation Indicator    -   N Neutral Activation Indicator    -   O Trendelenburg Activation

In another embodiment of the invention, the touch screen is removablefrom its position on the bed. It is therefore possible to use the touchscreen as a tool to explain the data stored in the control module orsimply to show it to the patient at times such as to explain thepatient's health status.

In another embodiment of the present invention, the touch screen canalso be equipped with one or more speakers to give instructions to thehospital staff. Hospital staff can use the touch screen to facilitatethe study of the data. A summary of the patient status can becommunicated by the touch screen. For example, the touch screen willhave the possibility to provide a weight summary of the patient andprovide, as the case may be, variations in the patient's weightthroughout a predetermined period of time. The touch screen can alsoassist the hospital staff for specific tasks such as calibrating thebed.

According to an aspect of the present invention, the control apparatusis highly adaptable in that its functionality can be changed or adjustedby updating the software stored in the flash or programmable memory. Thesoftware can be customized to the particular requirements of the user.With any change in function of the apparatus, the GUI of the controlapparatus can be altered and adapted to accommodate such changes.

In a further embodiment, the control apparatus can be adapted for use ina computer network. In a hospital, for example, a number of hospitalbeds can be remotely monitored from a central location such as a nursingstation. The software in a number of hospital beds can also be remotelyupdated or altered using a computer network. The ability to remotelyoperate the control apparatus is especially desirous where a patient hasbeen quarantined and contamination to the patient, hospital staff orequipment, must be minimized.

Control Interface Location

As discussed, the bed of the present invention can include one or morecontrol interfaces to facilitate the operator's use.

Head Control Location

In one embodiment, a control interface is located at the head-end of thebed. The head-end control interface can be an auxiliary to the othercontrol interfaces of the bed, such as the interface located on orproximate to the footboard, which is typically more convenient to accessto health care providers.

One of the advantages of this additional interface is that it providesfor easy and rapid adjustment of the bed by the operator duringtransport of a bed. This is important in situations when, for example,the patient must be rapidly moved into a prone position to facilitate anemergency medical procedure such as CPR, or to alleviate the onset of amedical condition that occurs while the patient is in transit.

Installation of an auxiliary control interface at the head-end of theapparatus allows the operator to adjust the position of the patientwithout having to physically move around the bed to access anothercontrol interface. This feature is advantageous when the bed is intransit and when another control interface is not easily accessible, forexample.

Other controls that are desirable to use when the head of the bed isaccessible can also be incorporated into the head-end interface, forexample, controls to peripheral devices. While the centered location ofthe head-end control panel is desirable, it can also be positioned toone side if required based on the design of the bed.

Duplicate Patient/Nurse Controls

In another embodiment of the invention, the bed comprises duplicatepatient/nurse control interfaces to allow for easy access to thecontrols by both the patient and a nurse. The control interfaces can betouch pad control panels, for example, that can be installed in alocation on the bed that is convenient for the respective users. In oneembodiment, a first control interface is installed onto an inner surfaceof a head side rail, for access by a patient, and a second control panelinstalled on an outer surface of a foot side rail, for access by anurse. In this way, should the foot side rail be lowered, for example,when a nurse is attending to the patient, the lying position of the bedmay still be adjusted using the control panel at the head side rail. Inanother embodiment of the invention, the control interfaces areinstalled onto a side rail and a headboard, respectively. In a furtherembodiment, the control interfaces are installed onto a side rail and afootboard, respectively.

The duplicate control interfaces of the present invention can beembedded into and, therefore, flush with the side rails, footboard,and/or headboard to allow the hospital bed, side rails, and controlpanels themselves to be easily cleaned. As well, the control interfacescan be positioned slightly inside of the perimeter of the side rail,footboard, and/or headboard in order to prevent accidental activation ofany of the features of the bed.

The control interfaces can be positioned in such a way as to facilitateviewing of the control panel. In one embodiment, the control panels areangled slightly, for example, upwards, to allow for ease of viewing ofthe control panel in the side rail device even when the side rail is inthe lowered position.

Control Panel Functions

In one embodiment, the operation of any feature of the bed is initiatedon a first come, first serve basis for a given actuator. For example,the same actuator cannot be simultaneously controlled from twolocations. Upon initial activation at one control panel, all othercontrols for operating that actuator are locked until release ortermination of the activation of the actuator.

Each location of the control panels can be used simultaneously tocontrol different features of the bed. For example, a control panellocated proximate the headboard may provide for the following bedmovement:

-   -   A Fowler up/down: Moves the head section about pivot    -   B Knee Gatch up/down: Moves the seat section about pivot    -   C Foot up/down: Moves the foot section about pivot    -   D Bed Height Control Up: Raises the height of the bed from the        surface    -   E Bed Height Control Down: Lowers the height of the bed from the        surface

This same control panel configuration can be located on the exterior ofthe head side rails.

Another embodiment of a control panel located on the exterior of thehead-end side rails may provide for the following bed movement:

-   -   A Fowler up/down: Moves the head section about pivot    -   B Knee Gatch up/down: Moves the seat section about pivot    -   C Foot up/down: Moves the foot section about pivot    -   D Reverse Trendelenburg: Raises the intermediate frame at the        first (head) end and lowers the intermediate frame at the second        (foot) end    -   E Trendelenburg: Raises the intermediate frame at the second        (foot) end and lowers the intermediate frame at the first (head)        end    -   F Bed Height Control Up: Raises the height of the bed from the        surface    -   G Chair Position: Places the bed in a chair position    -   H Bed Height Control Down: Lowers the height of the bed from the        surface    -   I Flat Bed Position: Places the bed in a flat position.

One embodiment of a pendant control interface comprises the followingfunctions:

-   -   A Raise Fowler: Raises the head section about pivot    -   B Lower Fowler: Lowers the head section about pivot    -   C Raise Knee Gatch: Raises the seat section about pivot    -   D Lower Knee Gatch: Lowers the seat section about pivot    -   E Caregiver Call: Alerts a caregiver that assistance is required    -   F Interactive Control Panel: Provides access to television,        radio, lighting, other.

Another control panel may be directed to the brake mechanism, can alsobe located on the exterior of the head-end side rails, comprising thefollowing functions:

-   -   A Brake Activation: Raises zoom actuator, places brake actuator        in Brake position    -   B CPR Activation: Places the apparatus in the CPR position    -   C Neutral Activation: Raises zoom actuator, places brake        actuator in Neutral position    -   D Steer Activation: Lowers zoom actuator, places brake actuator        in Steer position    -   E Battery Low Indicator: Indicates low battery power    -   F Call Maintenance Indicator: Indicates an error that cannot be        fixed by the user    -   G Trendelenburg Activation Indicator: Indicates the bed is in        Trendelenburg

For this control panel, components A, C and D are also indicators of thebrake status.

In other embodiments, the position of the control panels can be anywhereon the bed.

Message Indicators

The apparatus may have numerous system message indicators, optionallydisplayed on the control panels. For example, in reference to part G ofFIG. 29, indicators include Total Lockout, Call Maintenance, BatteryLow, Brake Not Set and Side rail Not Locked or Side Rail Down.

The Total Lockout lock mechanism blocks the control-panel from the siderails, footboard, pendant and head panel. When the lock mechanism isactivated, such as by pressing a user actuatable device, such as abutton, the corresponding lock icon illuminates. In one embodiment thebrake can be engaged during a total lockout but cannot be disengaged atany time during a total lockout. The lock mechanism does not affect thefunctions of the caregiver call, the scale system or the bed exitdetection. In another embodiment, the control panels located on thefootboard and the head panel may not be affected when the user activatesthe total lockout button. The different parameters for the lockmechanism are saved if there is a power outage and resume from theiroriginal state when the power is back to normal.

The Call Maintenance indicator is meant to indicate the need for repairsor support in regards to the proper functioning of bed system. Thisindicator is triggered by one or more monitoring sensors placed atvarious locations within the bed. The need to call maintenance can arisein situations where there are problems particularly associated with theelectronics of the bed, including overheating of the motors/actuators,non-functioning tilt sensors, loss of network links or “SAFE” errors.

The Battery Low indicator apprises the user on the level of powerremaining in the one or more batteries. It indicates the batteries arealmost out of power and require re-charging soon.

In one embodiment, there are two batteries. The time needed to chargeboth batteries completely is approximately 8 hours. The approximatecharge left on the batteries is determined by the amount of voltage thatboth of the batteries are able to provide to the system, according tothe following table and graph: Voltage Percentage 27.60 100 27.00 8024.00 20 22.10 0

From this graph, there are 3 linear graphs that are determined for whichthe amount of remaining charge on the batteries can be calculated. Forexample, if the batteries are currently providing a voltage of 27.2V,the following formula determines the percentage of charge left on thebatteries: $\begin{matrix}{\begin{matrix}{{Percentage}\quad{of}\quad{charge}} \\{{left}\quad{on}\quad{the}\quad{batteries}}\end{matrix}\quad = \left( {80 + \begin{pmatrix}{\left( {\left( {27.2 - 27} \right)/\left( {27.6 - 27} \right)} \right) \times} \\\left( {100 - 80} \right)\end{pmatrix}} \right.} \\{= {80 + {6.66\%}}} \\{= {87\%}}\end{matrix}$

Similarly, if a voltage of 25.0V is detected from the batteries, theamount of charge left on the batteries is calculated as: $\begin{matrix}{\begin{matrix}{{Percentage}\quad{of}\quad{charge}} \\{{left}\quad{on}\quad{the}\quad{batteries}}\end{matrix}\quad = \left( {20 + \begin{pmatrix}{\left( {\left( {25.0 - 24} \right)/\left( {27.0 - 24.0} \right)} \right) \times} \\\left( {80 - 20} \right)\end{pmatrix}} \right.} \\{= {20 + {20\%}}} \\{= {40\%}}\end{matrix}$

Finally, if the voltage detected from the batteries is of the order of23.0V, the percentage of charge left on the batteries is:$\begin{matrix}{\begin{matrix}{{Percentage}\quad{of}\quad{charge}} \\{{left}\quad{on}\quad{the}\quad{batteries}}\end{matrix} = \left( {\left( {\left( {23.0 - 22.10} \right)/\left( {24.0 - 22.1} \right)} \right) \times 20} \right)} \\{= {9.47\%}} \\{= {10\%}}\end{matrix}$

The Brake Not Set indicator is used to apprise the user that the brakesare not engaged on the bed. Such an indication assists to avoid healthcare personnel's inadvertently leaving the bed without the brakes beingset so as to avoid any inconveniences or injury to patients.

The Side rails Not Locked indicator is used to indicate if any siderails are not locked with the side rail locking mechanism. Thisindicator helps users prevent situations where patients are leftunattended with their side rails not locked.

Apparatus Positions

A would be understood, different positions can be achieved with thevarious user actuatable devices, such as the buttons display in FIGS.59A. In one embodiment, the desired angles for different positions canbe: Deck support Standard Enhanced 20 Section Flat Cardiac Chair CardiacChair Fowler (Head) 0 degree (State 0) 64 degrees (State 1) 80 degrees(State 2) Foot 0 degree (State 0) 30 degrees (State 1) 50 degrees (State2) Knee Gatch 0 degree 13 degrees 15 degrees (Seat)

When the user presses on the chair button, the sequence starts at thecurrent height. If the bed is in the Trendelenburg or the ReverseTrendelenburg position, the elevation system which is in the lowerposition between the two, is raised to reach 0 degree of Trendelenburg.If the bed needs to be raised so that the foot section reaches 50degrees without the interference of the foot panel with the surface, thebed is raised to a secure height to ensure no interference. In thisembodiment, when two elevation motors function, the other sections ofthe bed do not move.

There is a “soft stop” of about 1 second between each chair position tomake sure that the user wants to continue the sequence when button G(Chair) is still being pressed. When button G (Chair) is pressed, thestate of each section of the bed is calculated. The state to be achievedis always superior to the state of the section which is in the loweststate. For example, if the head section of the bed is in the state 0.5(between 0 and 64 degrees) and the foot section is in the state 1.5(between 30 and 50 degrees), the state to be achieved is 1. Every singlesection of the bed will thus move to be able to reach this state. Inthis example, the head or Fowler section is raised. Consequently, eachsection of the foot can move in both directions with the same button. Inone embodiment, the state of the Knee Gatch section is never used todetermine the state that needs to be achieved but it is used to informthe system as to whether a given position has been completed.

If one of the three locks (Fowler, Knee Gatch or Total) is activated, nomotion in regards to the Enhanced Cardiac and Cardiac chair sequences isallowed. This condition is independent of the position of the decksupport. Consequently, the bed will not carry out any motion whenbuttons I (Flat) or G (Chair) are pressed.

When button I (Flat) is pressed, the state of each section of the bed isalso calculated. The state to be achieved in this example is alwayslower than the state of the section which is the lowest. For example, ifthe Fowler section is in the state 0.5 and the foot section is in thestate 1.5, the state that needs to be reached is 1. Consequently thehead section is at 0 degree, Knee Gatch is at 0 degree and the footsection is at 0 degree.

In the event that button I (Flat) is pressed when the apparatus is inthe Trendelenburg or Reverse Trendelenburg positions, the bed will beset into motion such that both the Fowler and the seat sections willmove in order to achieve the flat position. In this example, the bedwill settle itself at the height of the “point (axis) of rotation” ofthe apparatus.

It is possible to move the Knee Gatch, head and foot sections at thesame time. In one embodiment, the motion of the bed stops if the userpresses on button C (Foot Button Down) and there is a possibility thatthere might be contact of the foot-end section with the surface.

The commands that are activated from the control panel of the headboardand the footboard are commands that are typically attributed to acaregiver such as a nurse. The commands activated from the pendant aretypically attributed to the patient. In one embodiment, the motions thatare requested from the caregiver have priority over the motionsrequested by the patient. In the event that the caregiver inputs severalsimultaneous motions in the control panel and it is not possible toactivate all the motors at the same time, the first requested motionwill be carried out first. The system does not allow several motors tobe put in motion at the same time. In one embodiment, other than themotors for the bed height, three motors can be put into motionsimultaneously. The motors for the height work together and none of theother motors can work simultaneously with them. Also, the motors for theFowler, Knee Gatch and foot sections can work together at the same time.

When two motions that are opposite to each other are requested by theuser (for example, simultaneous raising and lowering the bed) on thesame control panel, none of the requested motions are carried out. Insuch a case, the system stops all the motions. In one embodiment, thefootboard control panel takes priority over the side rail and pendantcontrol panels. If, for example, signals from the side rail controlpanel request to lower the apparatus while signals from the footboardcontrol panel request to raise the apparatus, the system will raise theapparatus. It does not matter if the motion for the bed to be loweredhas been initiated first before the footboard control panel function toraise is activated.

There are maximum angles with which the Knee Gatch section can bearticulated in relation to the angle of the foot section and vice versa.

If there is a mechanical constraint that prevents a requested motionfrom being completed, the constraint needs to be removed to allow forthe motion to occur. When the Knee Gatch section is raised and lowered,the foot section angle changes mechanically. Therefore the foot sectionneeds to be moved in such a way that it is able to maintain its angle ofinclination.

The Trendelenburg position is achieved when the Fowler (head) section isset to the low position while the foot section is set to the highposition. This particular position can be achieved such as by pressingbutton E (Trendelenburg) until the desired position is obtained. Incontrast to the Trendelenburg position, the Reverse Trendelenburgposition occurs where the Fowler (head) section is set to the highposition and the foot section is set to low. This is achieved bypressing button D (Reverse Trendelenburg). There is a maximum angle ofinclination that can be achieved during the Trendelenburg and ReverseTrendelenburg positions. Typical angles of inclination for theTrendelenburg position and Reverse Trendelenburg position are 15degrees.

With respect to the elevation system motors, the speed is decreasedsince the mass is not necessarily uniformly spread on the bed and thetwo motors do not necessarily have the same characteristics.Consequently, the angle of Trendelenburg is calculated when the motionis initiated and the speed of the fastest motor is adjusted so that theangle of inclination in the Trendelenburg mode is maintained duringraising or lowering of the apparatus. In one embodiment, the amount oftime needed for the bed to reach the highest position when it wasinitially at the lowest position is not more than 35 seconds.

During the Trendelenburg and Reverse Trendelenburg motions, there areminimum angles that need to be respected for the elevation system. Inone embodiment, the elevation system for the head is not lowered to aheight where the corresponding angle is less than 20 degrees during theTrendelenburg position. A similar restriction exists for the elevationsystem during the Reverse Trendelenburg position. Consequently, if thebed is in the lowest position and the user wants to move to aTrendelenburg position, the elevation system for the head is firstraised (even if, under normal conditions, the elevation system for thehead is lowered during the positioning for Trendelenburg) to avoid anyinterference. The elevation system for the head will sufficiently riseto avoid any possible interference, which at the limit is 15 degrees ofTrendelenburg.

Similarly, if the bed is at a height with a low angle of Trendelenburgand the user wants to lower the bed by pressing the Bed Height ControlDown button, the bed is lowered by keeping the same angle ofTrendelenburg as explained above until the elevation system for the headreaches a minimum angle in the Trendelenburg position. At such an angle,the elevation system for the head will stop its motion and the elevationsystem for the foot will continue its decline if the user continues topress on button H. The same logic is applicable for the elevation systemfor the foot and the position is Reverse Trendelenburg.

In one embodiment, the angle between the Knee Gatch (seat) section andthe Fowler (head) section are never less than 90 degrees. An anglesmaller than degrees would eventually result with the patient beingstuck in an uncomfortable position. If the user desires to raise theKnee Gatch section and the 90 degree limit is reached, the system willautomatically lower the Fowler section to avoid such an acute anglesituation. Similarly, if the user raises the Fowler section and the 90degree limit is reached, the system will automatically lower the KneeGatch section.

During Reverse Trendelenburg motion, the angle of the head section ismonitored to ensure that the sum of the two angles is not more than 90degrees. For example, if the head support is at 80 degrees, and the userwants to set the bed to the Reverse Trendelenburg position, there is adanger that the patient may be ejected from the bed if the sum of thetwo angles is above 90 degrees.

V. Bed-network Communication Systems

A network connection is integrated into a plurality of hospital bedsthat provides an information or data link between each bed and thecomputing network of the care facility. This data link provides a meansfor the transfer of information between the bed and the care facility,thereby enabling patient information to be transferred to the bed, andbed diagnostic information to be transferred to the computing network.Data transfer is provided by a wired or wireless data link.

The information that can be transferred from the computing network tothe bed can include patient data for example, test results, personalhistories, or other patient related information. Furthermore, beddiagnostic information, current location, and patient informationevaluated by the bed, for example can be transferred from the bed to thecomputing network. The transfer of information via the data linkprovides a means for remote access to the information determined andcollected by the bed and remote monitoring of both the bed and thepatient. In addition, the data link enables the remote updating of bedsoftware and operational parameters when desired.

The data link enables the centralization of patient and bed monitoring,which assists in providing enhanced and more efficient patient care, bedservicing and maintenance, and efficient bed allocation based on patientrequirements, for example upcoming procedures and required bedrequirements for these procedures, thereby reducing patient transfers ifan appropriate bed is originally allocated.

Multipoint Control Architectures

The network connection integrated into the hospital beds of the presentinvention is, in one embodiment, a communication network embedded in thebed having a multiple control point architecture. The network is basedon Controlled Area Network (CAN). Several processors are connected tothe network, each processor being capable of controlling variousfunctions. Each function can be controlled by one processor or byseveral processors connected to the network. The types of functions tobe controlled in this manner are button reading functions, motiondecision functions, scale system functions, and functions related to thebed exit system. In this type of configuration, multiple functions canbe computed simultaneously from different processors of the controlpoints in the network. Where the same function is computed from twodifferent control points, a priority mechanism decides which functionwill be performed.

One feature of the network is the multiple control points associatedwith specified functions allowing simultaneous computing of functionsand the priority or conflict resolution mechanism. This improves themotion security of the bed, diminishes the impact of the processors'computing limitations, improves response time and reduces the length ofthe cables required in the network. Such multiple control pointarchitecture is also compatible with any bed having a pre-existingCAN-based embedded communication network.

Universal Communication System

In one embodiment, the hospital bed is adapted to wirelessly communicatewith a hospital network to transmit bed data between the bed and thehospital network. The network may comprise wired and/or wirelesscommunication paths. In addition, communication can occur in adistributed manner, from bed to bed to bed from the beds to more thanone available hospital network, or from the beds to more than one remotestation. Also, communication can occur directly, using dedicated wiredor wireless networks, from the beds to the remote station located on thehospital network.

The bed data may include information such as:

-   -   a bay location of the bed    -   a position of side rails of the bed    -   status of bed brakes, e.g., brakes set/brakes not set    -   housekeeping status of the bed, e.g., whether the bed is clean,        dirty, or in the process of being cleaned    -   a height of the bed    -   an angle of the head-end of the bed, e.g., a fowler angle    -   a weight of a patient on the bed    -   a status of a bed exit system, e.g., is the bed exit system        active or inactive    -   bed maintenance data and history    -   bed usage data and history    -   bed scale ‘zero’ status    -   patient location    -   patient movement    -   patient motion tracking    -   the patient's weight history    -   location of non-bed devices associated with the bed

The information is transmitted either wired (e.g., Ethernet) orwirelessly (e.g., WiFi) by the bed, directly or indirectly, to a remotestation (e.g., central nurses station) located on the hospital networkwhere the data and/or information received is processed to configure orcontrol the bed or other various systems. In one embodiment, the remotestation is positioned at a central nurse's station in the healthcarefacility and is implemented in a workstation, e.g., a personal computer,for use at the central nurse station. The workstation may includesoftware configured to manipulate data and/or information received fromthe various systems or the hospital bed. For instance, the workstationmay be configured to receive data and/or information from thecommunication module of the bed or to transfer data and/or informationback to the bed. Such data may originate from a bed exit detectionsystem, a bed height detection system, a weight scale, a side railsensing system that detects a position of the side rails, a therapymattress, and the like. The remote station preferably includes agraphical user interface on a touch-screen display for reviewing andmanipulating the data and/or information. It should be appreciated thatthe remote station may also be a stand-alone unit that is not located onthe network, but includes the necessary hardware to link to thecommunication module of the bed.

Other systems on the hospital network may also have access to theinformation. These systems may include an asset management system, a bedmanagement system, an admission/discharge/transfer system (ADT), patientthroughput systems, eICU systems for the remote monitoring of criticallyill patients, a nurse call system for facilitating patient contact witha healthcare professional, or any one of several existing or futureinformation systems. The information can be presented at the bed, withinthe room, outside of the room or at any other location, including theremote station, or any other networked display, including any mobiledevices or displays such as personal data assistants (PDAs), wirelessbadges, phones, and the like. The information can also be transmittedwirelessly from bed to bed (daisy-chained) until the data is received bya wired network node.

For instance, the control system may comprise multiple nodes arranged ona bus for acquiring, transmitting, and receiving the information. Itshould be appreciated that any number of configurations of the controlsystem are possible to carry out the communication.

A bed exit node receives signals from multiple bed exit sensors todetect movement of a patient on the bed. A side rail sensing nodereceives signals from multiple side rail sensors to detect a position ofeach of the side rails. A bed articulation/height node receives signalsfrom a bed height sensor to determine a height of the bed and from afowler angle sensor to determine the fowler angle of the head-end of thebed. A brake set node receives signals from a brake set sensor todetermine whether or not the bed brakes are set. Additional nodes couldalso be contemplated such as a scale node for monitoring a patient'sweight and weight history, a patient node for monitoring a location of apatient and movement of a patient, and a non-bed node for monitoring thestatus or location of non-bed devices such as patient monitoring,diagnostic, or treatment devices. Each of these nodes may include aprocessor for processing the raw sensor signals and are adapted tobroadcast the respective information for receipt by the remote stationvia a communication node. The communication node transmits informationfrom the other nodes to another bed, one of several hospital networks,or the remote station via a cable, a wireless router, transceiver, orother wireless device, and receives information from the same for use bythe other nodes. In some embodiments, both wired and wirelessconfigurations are present on the hospital bed to easily accommodateuser preferences. It should be appreciated that two or more nodes may becombined into a single node to carry out these functions. The particularconfiguration of the control system nodes is not intended to belimiting. In fact, these “functional” nodes can be separate or combined,using one or a plurality of sensors, transducers and processors tomonitor the described conditions. In one embodiment the control systemcomprises a plurality of electronic nodes or modules that communicate ona peer-to-peer network. In another embodiment of the invention, thecontrol system is a master/slave system utilizing a central processingunit (CPU) that is physically supported by the hospital bed and is inelectronic communication with the network via a communication module.The CPU includes the necessary processors and memory for carrying outthe functions of the hospital bed in response to user input as will beappreciated by those skilled in the art.

By providing the communication node/module on the hospital bed, thehospital bed acts as a communication center or link for transmittingdata and/or information related to the hospital bed to the network.

Room Location Module/Location Detection System

In one embodiment, the hospital bed comprises a location detectionsystem for locating beds in a facility, and specifically detects the bedbay or zone in a room that a bed is located. A room location module maybe mounted at each bed bay location in each room of the hospital. Theroom location module could be mounted on the ceiling, wall, floor, orany location that permits the room location module to carry out itsintended function. The room location module is programmed with a bed baylocation ID to transmit to the bed once the bed has “docked” with theroom location module. The location ID may simply be a serial number ofthe location module that is entered into a look-up table stored inaccessible memory of the remote station and associated with the bed bayin which the location module is installed. In one embodiment, a motiondetector is integrated into each room location module to detect when thebed is moved into the associated bay location.

Once the bed is detected, a synchronization cycle is initiated. In oneembodiment, the room location module, via a room module transmitter,wirelessly transmits the bed bay location ID to a bed receiver locatedon the bus so that the bed “knows” its bay location. The bed baylocation ID can then be broadcast over the bus to the communication nodeand to the remote station. As a result, the bed acts as a communicationlink between the location module and the remote station. A separatelook-up table is utilized by the remote station to correlate thelocation ID to a patient for which the specific bed is associated. Theremote station then correlates the location ID and patient to theparticular bed bay or zone in which the specific bed is now located suchthat the software application installed on the remote station canaccurately manage data corresponding to the specific bed and thepatient.

The room location module can use a variety of systems for transmittingand receiving the bed bay location ID. In one embodiment, the locationmodule includes at least one infrared (IR) transmitter for transmittingthe bed bay location ID to the receiver and the receiver includes atleast one IR sensor for receiving the bed bay ID from the IRtransmitter. In another embodiment, the location module may include aradio frequency identification (RFID) tag for transmitting the locationID using radio frequency. A person skilled in the art will appreciatethat a variety of known RFID systems, including, active, semi-active,and passive RFID systems, can be utilized. Examples of such RFID systemsinclude, without limitation, an RFID tag mat that includes an array ofRFID tags, an RFID swipe card having at least one active or passive RFIDtag, or a magnetic RFID tag. Other embodiments of the invention caninclude one of: an ultrasonic transmitter for transmitting the locationID using ultrasonic signals; an inductively coupled transmitter fortransmitting the location ID using principles of magnetic inductivecoupling; or a modulated light transmitter for transmitting the locationID using modulated light. It should be appreciated that in each of theseembodiments, the receiver is particularly adapted for receiving thespecific signal types mentioned, i.e., the receiver may be a RFIDreader, or include an ultrasonic sensor, an inductively coupled sensor,or a modulated light sensor. In another embodiment, the location moduleuses WiFi technology, or a mesh network, to transmit and receive bed baylocation IDs. In a further embodiment of the invention, the locationmodule comprises an ID transmitter integrated into a power cordinterface to communicate with the ID transmitter through a power cord.The receiver would then communicate the location information, e.g., bedbay location ID, to the remote station located on the network. In yetanother embodiment of the invention, the location module comprises anEthernet port and the receiver comprises an Ethernet transceiver forcommunicating the location information to the remote station. In afurther embodiment, the location module uses a combination of thesemethods for transmitting and receiving the bed bay location ID.

In another embodiment of the invention, the location detection systemallows locating a bed by separately determining first and second areasof the location. In one embodiment, the first area is the room, e.g.,Room 1, in which the bed is located, and the second, subarea, is thezone in the room in which the bed is located, e.g., zones A, B. In thisinstance, a first location module would be enabled to only provide firstarea or room locations, and not specific zone locations, to a remotestation. A second location module associated with the bed and inelectronic communication with the remote station would be enabled totransmit a second location ID to the remote station. The second locationID corresponds to the subarea or zone in which the bed is located. Thus,the first location ID provides the general vicinity in which the bed islocated, while the second location ID further refines the description ofthe location to pinpoint the location of the bed. The second locationmodule would be adapted to generally measure distances from wallslocated in the first area, e.g., Room 1, to further determine theposition of the bed in the room. Sonic distance sensors, laser distancefinders, or a hall-effect sensor operable with a room magnet orplurality of room magnets located in the room, can be employed todetermine the zone location of the bed, for example.

As mentioned above, the bed bay location ID can also be correlated to apatient ID provided by the ADT system. As a result, the display at theremote station can indicate both the bed bay location ID and thecorresponding patient ID. The room location module may be a standaloneor networked device. When acting as a standalone device, the roomlocation module simply comprises a battery-powered transmitterpre-programmed with the bed bay identification such that the hospitalbed is able to determine its location even when the hospital network isunavailable.

The room location module could also include additional features toprovide an intelligent room module. For instance, the intelligent roommodule may include interface buttons for operator selection thatcorrespond to the bed or room being clean, dirty, empty, occupied, readyfor occupancy, etc. An alternative intelligent room module may alsoinclude a graphic display such as a touch-screen display with multiplenested user screens to access or transmit patient, bed, or room data.The intelligent room module may transmit this information, e.g.,bed/room clean/dirty, etc., directly or indirectly to the hospitalnetwork, beds or remote station, using wired or wireless communicationpaths. Communication can occur from the intelligent room modulesdirectly to the hospital network, from the intelligent room modules tothe beds then to the hospital network or to more than one availablehospital network, or directly from the intelligent room modules to theremote station or to more than one remote station. The intelligent roommodules may also be configured as wireless access points between thebeds and multiple non-bed devices such as patient monitoring devices,patient treatment devices, diagnostic devices, and the like, or theintelligent room modules may be configured as wireless access pointsbetween the hospital network and the non-bed devices.

Bed Configuration Status Indicator

In one embodiment of the invention, the hospital bed comprises a systemfor monitoring a plurality of bed conditions. A status indicator node,in communication with the bus and the other nodes, is configured, aspart of a bed status indication system, to establish a “desired” bedconfiguration based on a user-defined set of conditions to be monitored,monitor the user-defined set of conditions, and trigger an associatedaudible or visual indicator responsive to the monitored conditions toindicate whether the hospital bed is in the “desired” or an“undesirable” configuration, i.e., when one or more of the monitoredconditions are in an “undesirable” state.

If each of the user-defined monitored conditions are in the “desired”state, a green indicator light is illuminated to indicate that the bedis in the desired configuration. If any one of the monitored conditionsis not in the “desired” state, an amber indicator light is illuminatedto indicate that the bed is not in the desired configuration. Of course,the status indicator node can be configured with any number of monitoredconditions, or as few as one monitored condition. The indicator lightsare preferably duplicated on a footboard user interface of the bed alongwith controls for other conventional features of the bed. Any suitableindicating devices may be used in place of or in addition to the greenand amber indicator lights, such as audible alarms and the like, whetherlocal or remote. The indicator lights are merely exemplary. In addition,if the bed is not in the desired configuration, a light positioned on acomponent that is out of place may be used to indicate that it needs tobe moved, e.g., a light on one of the side rails. A text display on thefootboard user interface or other location may also provide informationas to which conditions are not in the “desired” state. The “desired”state for each monitored condition, e.g., side rail position, bedheight, fowler angle, etc., can be modified as the patient's conditionchanges or based on standard hospital criteria, or the “desired” statescan be reset to a predefined ‘pre-set’ configuration in the event of asignificant clinical event such as surgery, or when a new patient isadmitted.

Examples of “desired” states for monitored conditions may include:

-   -   side rails in an up position    -   bed brakes set    -   bed height is below a predetermined level    -   fowler angle is thirty degrees    -   bed exit detection is active, e.g., alert is given if patient        exits bed    -   other patient or hospital specific conditions    -   bed is identified with a bay location    -   housekeeping status: bed occupied    -   the weight of a patient on the bed    -   bed scale ‘zero’ status    -   patient is positioned proximal to the bed    -   nurse is positioned proximal to the bed    -   infusion pump is positioned proximal to the bed    -   patient movement is regular and moderate

In a further embodiment, a single global “correction” button on thefootboard user interface of the hospital bed could transmit a signal tothe status indicator node upon actuation to automatically activate aplurality of actuators (not shown) to “correct” the conditions that arenot currently desired, such as by automatically raising the side rails,setting the brakes, lowering the bed height, adjusting the fowler angle,activating the bed exit system, and the like. The actuators are inelectronic communication with the control system via the bus and maycomprise motors, pumps, valves, solenoids, or any other mechanical orelectrical devices capable of correcting the monitored bed conditions.The global correction button could also be a user-selectable button onthe display at the remote station, or at any other networked location.

Fowler Monitoring System

As discussed, certain bed configurations may be desired to accommodatepatient events (e.g., surgery) or clinical conditions (e.g., ventilatorinduced pneumonia (VIP)). In many of these cases, it may be desired thata clinically preferred fowler angle of the bed be indicated or requiredper accepted clinical standards. For example, a particular fowler anglemay clinically improve respiration and may reduce the risks ofcontracting ventilator induced respiratory diseases such as VIP. In oneembodiment of the invention, therefore, the hospital bed comprises afowler monitoring system for monitoring and controlling the fowler angleof the head-end of the bed.

A fowler monitoring system, of the present invention, can be activatedby a nurse or other operator via a touch button or other interface (suchas at a footboard user interface), which instructs the bedarticulation/height node to monitor the fowler angle and sound an alarm(not shown) or give other notification when the fowler angle is too low.The fowler monitoring system can also be configured to modify the“desired” configuration of the hospital bed by providing a predefined“desired” configuration of the hospital bed, i.e., the fowler anglewithin a predetermined range, to be monitored by the status indicatornode. Other medical or clinical conditions may have predefined “desired”configurations that can be programmed into the status indicator nodesuch that, when appropriate, a user can select these predefined“desired” configurations either at the hospital bed or the remotestation, or other networked station for monitoring.

The fowler monitoring system can also track the fowler angle over timeand provide associated statistics. For instance, the fowler monitoringsystem can determine how long the fowler angle has been over thirtydegrees in the last 24 hours with associated date/time stamps such thatthe operator can determine when the fowler angle fell below thirtydegrees. The fowler monitoring system can also be configured toautomatically log the date/time when the fowler angle was below thirtydegrees for immediate viewing by hospital personnel either locally, orat any remote station, including personal pagers, phones, radios,tablets, viewing screens, data assistants or any other means tocommunicate and present data to the clinical staff. In addition, the BedStatus system could proactively message the clinical staff based upon aconfigurable ‘clinical response network’ that would provide theappropriate level of response to a number of anticipated clinicalsituations. All of this data can also be associated with the patient IDthrough an interface (not shown) with the ADT system, or any otherinformation system as previously discussed.

For further examples of functions, controls, and other systems that maybe incorporated into the bed of the present invention, reference is madeto copending U.S. applications entitled PATENT HANDLING DEVICE INCLUDINGLOCAL STATUS INDICATION, ONE-TOUCH FOWLER ANGLE ADJUSTMENT, AND POWER-ONALARM CONFIGURATION, Ser. No. 11/557,349, filed Nov. 7, 2006; LOCATIONDETECTION SYSTEM FOR PATIENT HANDLING DEVICE, Ser. No. 11/277,838, filedMar. 29,2006; and DIAGNOSTIC CONTROL SYSTEM FOR A PATIENT, Ser. No.11/362,365, filed Feb. 23, 2006, which are herein incorporated byreference in their entireties.

The Use of Loads Cells and Tilt Sensors to Monitor Patients on aHospital Bed

As described above and referring to FIGS. 5-7 and 17A-17D, load cells602 can be positioned at one or more locations in the frame system ofthe bed such that measurements of various load signals can be achieved.Load cells generate load signals indicative of forces applied to theload cells.

Accurate load cell readings are important for various reasons such asdetermining the weight fluctuations of a patient over time and thepatient's center of gravity at any given time.

FIGS. 5-7 and 17A- 17D illustrate one embodiment of the presentinvention where the load cells 602 are respectively located proximate tothe four corners of the intermediate frame, with the intermediate framebeing operatively connected to the load frame via the system of loadcells. More specifically, the load cells are coupled with the respectiveends of the superior components of the intermediate frame and withcomplementary areas on the inferior components of the load frame. Thesuperior components of the intermediate frame and the inferiorcomponents of the load frame are longitudinally adjacent but are not incontact, the sole physical connection between these components beingthrough the load cells.

In a hospital bed according to one embodiment of the present invention,the load cell measurements can be used together with other measured orinput information, such as the articulation angle of a section of thelying surface support or the entire load frame in order to determine,for example, a patient's weight. For example, when the patient supportis angled to the Trendelenburg and reverse Trendelenburg positions, theactual load can be calculated by knowing the angle of the load frame andrespective loads measured by each load cell, independent of the loadframe's position. As depicted in FIG. 44, one or more tilt sensors 603a, 603 b can determine the angular position of the load frame while theload's center of gravity shifts.

Medical personnel require accurate readings of the patient's weightindependent of the bed's articulation. Such a measurement is possible bycalculating the bed's angle relative to baseline and load cellmeasurements.

A tilt sensor, which incorporates an accelerometer, is attached to anypart of the frame system that can be elevated, angled and/orarticulated.

The tilt sensor provides a signal that is read and measurements arecalculated after a given time period, such as 50 ms. It can runcontinuously, intermittently or upon command from the user, such as whencomponents of the frame system are in an articulated position. The tiltsensor is connected to at least one mdtherboard, processor or anyelectronic board via a communications network, fiber optic, or wirelessconnection to allow for a reading of the tilt sensor signal.

In one embodiment, the tilt sensor is designed with a solid stateaccelerometer, such as the ADXL202E accelerometer from Analog Devices,Inc. of One Technology Way, Norwood, Mass., schematically represented inFIG. 62. Angular solid state sensors or electronic angular sensors,where a change in angle of the sensor changes the impedance of thesensor which can be measured, could also be used. Other accelerometersmay also be used within the present invention, as would be understood bya worker skilled in the art to which this invention relates. Theaccelerometer of this embodiment is a 2-axis acceleration sensor with adirect interface to low-cost microcontrollers. This interface ispossible through a duty cycle (ratio of the pulse width to the totalperiod) output. The outputs of the accelerometer can be analog ordigital signals whose duty cycles are proportional to acceleration. Theoutputs can be directly measured with an integrated microprocessorcounter, without any external converter.

FIG. 64 depicts a functional block diagram of the accelerometer used inthis embodiment. For each axis, a circuit output converts the signalinto a modulated duty cycle that is decoded by the microprocessor. Theaccelerometer of this embodiment must be capable of measuring positiveand negative accelerations to at least ±2 g, so as to measure staticacceleration forces such as gravity and therefore be used in a tiltsensor.

Theoretically, a 0 g acceleration produces a 50% nominal duty cycle.Acceleration is calculated as follows:A(g)=(T1/T2−0.5)/12.5%T2(s)=R _(SET)(Ω)/125 MΩ

The 12.5% corresponds to the theoretical gain of the accelerometer. Whenused as a tilt sensor, the accelerometer uses the force of gravity asthe input vector to determine the orientation of the object in space.The accelerometer is more sensitive to tilt when its reading axis isperpendicular to the force of gravity, that is to say, parallel to theearth's surface. When the accelerometer is orientated on axis togravity, that is to say, near its +1 g or −1 g reading, the change inoutput acceleration per degree of tilt is negligible. When theaccelerometer is perpendicular, the output varies nearly 17.5 mg perdegree of tilt, but at 45 degrees the output only varies 12.2 mg bydegree and the resolution declines. This is illustrated in the followingtable:

It is also to be noted that the gravity value varies according to thesine of the angle, which also influences the precision and consequentlythe orientation of the tilt sensor of this embodiment. The sensorprecision can be improved by using both Xout and Yout signals in theangular determination. By doing so, the low sensitivity range (around 0degrees) is reduced.

The tilt sensor circuit used in one embodiment was therefore designedfrom the Analog Devices Inc. accelerometer following the recommendeddesign parameters. The schematic of the circuit for this embodiment isshown at FIG. 65.

D1 is added to protect the circuitry against polarity inversion.

R_(SET) value was set to 1 MΩ. Therefore, T2 value is:T2=1M106 /125 MΩ=0.008

T2 total period is thus 8 ms, therefore giving a 125 Hz frequency.

In order to determine the actual values of the zero and the gain, thetilt sensor circuit must be calibrated. Since the zero and the gain areknown after calibration, only T1/T2 is unknown. It is this duty cyclethat varies according to the angle. The microprocessor thus reading andcalculates the corresponding angle.

The tilt sensor circuit comprises an analog potentiometer which outputsa PWM (pulse Width modulation) signal with a good signal-to-noise ratio.This PWM signal is sent to a microcontroller wherein the period of thesignal is measured and the on-time of the signals. A ratio of theseresults is proportional to the sine of the angle. By using the cosine ofthis angle within a formula (discussed below) the precise angle can bedetermined. This analysis can be accomplished by a microprocessor.

To calibrate the tilt sensor circuit, two duty cycle readings must betaken at known angles. With these two PWM readings, the two unknowns(zero and gain) can be computed. It is preferable to take a PWM readingwhen the tilt sensor is at its zero position, as readings are usuallyprecise at this position. This also provides a reading of the PWM valuecorresponding to the zero of the tilt sensor, since a sensor in zeroposition gives 0 g.

The tilt sensors of this embodiment are used to indicate the angle ofthe load frame, such as the Trendelenburg and reverse Trendelenburgangles. A compensation of the weight read by the load cells according tothe Trendelenburg angle can then be computed. Consequently, the weightvalue displayed is thus in the required margin.

As previously indicated, the axis in which the tilt sensor is positionedis important to obtain precise readings. For example, the position of ahead section of the lying surface support may vary between 0 and 80degrees. Given that the tilt sensor of the embodiment is more precisefrom −45 to 45 degrees than from 0 to 90 degrees, the tilt sensor wouldbe positioned in the bed so that the zero of the sensor is at 45degrees. In computation, one would account for this position by adding45 degrees to each angle read.

The calculation of load and calibration values is readily apparent inreferring to FIGS. 66 and 67, where:

-   -   X patient load;    -   Y₊ weight of patient support frame which changes with the        Trendelenburg angle;    -   Z₊ load cell factor which is not influenced by the Trendelenburg        angle;    -   Y⁻ weight of bed frame which changes with the reverse        Trendelenburg angle;    -   Z⁻ load cell factor which is not influenced by the reverse        Trendelenburg angle;    -   θ bed frame angle; and    -   T load cell readings.        Atθ=0°, T _(0°) =X+Y ₊ +Z ₊        Atθ=12°, T ₁₂°=(X ₊ +Y ₊)cos θ+Z ₊

During calibration, the load frame without the patient is measured at 0°and at 12°, providing: $\begin{matrix}{X = 0} \\{{T_{0}{^\circ}} = {{first}\quad{measurement}\quad{at}\quad 0{^\circ}}} \\{{T_{12}{^\circ}} = {{second}\quad{measurement}\quad{at}\quad 12{^\circ}}} \\{{T_{0}{^\circ}} = {Y_{+} + Z_{+}}} \\{{T_{12}{^\circ}} = {{Y_{+}\cos\quad\theta} + Z_{+}}} \\{Y_{+} = {{T_{0}{^\circ}} - Z_{+}}} \\{{Y_{+}\cos\quad\theta} = {{T_{12}{^\circ}} - Z_{+}}} \\{Y_{+} = \frac{{T_{12}{^\circ}} - Z_{+}}{\cos\quad\theta}} \\{{{T_{0}{^\circ}} - Z_{+}} = \frac{{T_{12}{^\circ}} - Z_{+}}{\cos\quad\theta}} \\{Z_{+} = \frac{{T_{12}{^\circ}} - {T_{0}{{^\circ}cos}\quad\theta}}{1 - {\cos\quad\theta}}} \\{{{if}\quad\theta} = {12{^\circ}}} \\{Z_{+} = \frac{{T_{12}{^\circ}} - {T_{0}{{^\circ}cos}\quad 12{^\circ}}}{1 - {\cos\quad 12{^\circ}}}} \\{Z_{+} = {\left( {{T_{12}{^\circ}} - {T_{0}{^\circ}*0.97815}} \right)*45.761565}} \\{Y_{+} = {{T_{0}{^\circ}} - Z_{+}}}\end{matrix}$

Z₊ and Y₊ for each load cell are determined during calibration. In asimilar manner, Z⁻ and Y⁻ are determined using measurements at 0° and−12°, providing:Z ⁻=(T _(−12°) −T _(0°)*0.97815)*45.761565Y ⁻ =T ₀ −Z ⁻

When determining the patient's weight, X, the following calculations aremade for each load cell: $\begin{matrix}{T_{\theta} = {{\left( {X + Y} \right)\cos\quad\theta} + Z}} \\{T_{\theta} = {{X\quad\cos\quad\theta} + {Y\quad\cos\quad\theta} + Z}} \\{{X\quad\cos\quad\theta} = {T_{\theta} - {Y\quad\cos\quad\theta} - Z}} \\{X = \frac{T_{\theta} - {Y\quad\cos\quad\theta} - Z}{\cos\quad\theta}} \\{X = {\frac{T_{\theta} - Z}{\cos\quad\theta} - Y}}\end{matrix}$

The processor determines the load frame's angular position(Trendelenburg or reverse Trendelenburg) prior to choosing Y₊ or Y⁻ andZ₊ or Z⁻. When the load frame's angle is 0°, the processor chooses Y₊and Z₊ to calculate the load.

The center of gravity can be calculated as follows, using for examplefour load cells (schematically represented in FIG. 62) positioned in arectangle relative to the patient:

-   -   X length (head to foot)    -   Y width (left to right)    -   LC(0) load cell value foot left    -   LC(1) load cell value head right    -   LC(2) load cell value foot right    -   LC(3) load cell value head left    -   W total weight of the patient    -   H(X) distance between the head load cells and foot load cells    -   H(Y) distance between the right load cells and left load cells        ${{CG}\lbrack X\rbrack} = {\frac{{{LC}(3)} + {{LC}(1)}}{\frac{W}{100}}*{H(X)}*0.01}$        ${{CG}\lbrack Y\rbrack} = {\frac{{{LC}(3)} + {{LC}(0)}}{\frac{W}{100}}*{H(Y)}*0.01}$

This embodiment of a load cell system can be used for monitoringmovement of a patient. The system can be integrated into the bed or canbe part of a lying surface such as a mattress. In addition, the loadcell system can comprise a number of load cells or load sensors, forexample a load cell which can be embedded in the bed proximallypositioned at each of a supported person's limbs and optionally at thecenter of the bed. The load cell system also can be comprised of a meshof load cells for example. The signals from the load cells can bemonitored and processed by a processing unit in the load cell system ora central processing unit capable of monitoring, processing, andcontrolling signals from the bed's various subsystems. Instead offorming part of a lying surface such as a mattress the load cell systemcan also integrated into the lying surface support. The load cell systemcan provide a measure for the pressure, weight, or mass load of acertain load cell, for example foot left or right load cell values andhead left or right load cell values and additional information about thelocation of the center of gravity.

In one embodiment of the present invention, the tilt sensors can providea means for determining possible interference between components of thebed. For example, if a particular component is in a certain relativeposition, a second component might not be able to perform certainfunctions associated with it. In this embodiment, there can furthermorebe a movement termination based on the evaluation of tilt sensorsreadings.

In a further embodiment of the present invention, tilt sensors can beused to evaluate a patient's position over a period of time through thecollection of angle variation data.

In one embodiment, a collection of angular data from the tilt sensorscan also provide assistance for the maintenance of the bed. For exampleit can help to determine the angle of a particular bed component and theperiod of time that that position is held, especially when a particularposition results in higher stress levels being applied to specificcomponents of the bed.

In another embodiment of the present invention, tilt sensors can bepositioned on the elevation system for determination of the height ofthe bed surface.

In another embodiment of the present invention, tilt sensors arewireless. In a further embodiment, tilt sensors do not have an on boardpower supply and are powered in the same way as for example an RFID tag,by the scanning frequencies sent by a scanner for example. In anotherembodiment, tilt sensors are integrated within load cells.

A worker skilled in the art would understand that tilt sensors could bepositioned in a plurality of other components of the bed, for example,the side rails, a control panel, on an intravenous apparatus supportattached to a bed, etc.

In one embodiment the control and diagnostic system can comprise anadditional scale subsystem providing a calibration process forcalibrating the scale subsystem to provide accurate reading of apatient's weight and subsequently to calibrate a motion detection systemfor monitoring movement of the patient. It may be necessary to calibratethe load cells' electronics in order to provide match the sensor signalswith the scale subsystem electronics.

In one embodiment, the tilt sensors can be used with a control anddiagnostic system as a means for fault detection. For example, where nochange in an angle is detected when an actuator is being activated tomodify the angle, the situation can be indicative of a blockage relatedto the actuator movement or an actuator malfunction.

FIG. 68 illustrates a schematic view of a console, which can be part ofa user interface embedded into a bed. The console can be integrated intothe footboard of the bed illustrated in FIG. 1 and provide access to thebed's functions. The console has backlit zone indicators, which canindicate a set zone mode of the bed for indicating a preset restrictionlevel for movement of a supported person. Indicators can also bemulti-color backlit to provide an indication of whether the system is inan armed or a disarmed state.

Buttons can be used to set and switch between the zone alarm asindicated by the zone alarm indicators. Buttons can arms or disarm thezone alarm functionality in a toggling fashion. Buttons can be sectionalor full color or multi-color back-lit to indicate an armed or disarmedstate of the zone alarm system. Interface elements can be used to raiseor lower the bed surface. While pushing the arrow-up button the bedraises and while pushing the arrow-down button the bed lowers. Pushingand holding both buttons and may cause the movement to stop or continuethe movement according to the button which was pressed first. Button canlock out some or all functionality accessible through this or otherconsoles until the button is pressed again. Buttons can be used tolock-out access to reorient the respective head and knee sections of thebed. Button, when pressed, causes the bed to assume a cardiac positionor other predetermined shape of the bed surface. Each of buttons whenpressed individually inclines or reclines the overall bed surfacewithout affecting the shape of the bed surface. Interface elementsprovide button groups which when pressed can reorient the head or theknee sections of the bed and can be used in order to achieve respectivedesired angles between the upper body and the upper leg, as well as theupper leg and the lower leg of a supported person. Display can be usedto display information about certain functions or the state of certainparts of the bed and its system components. Button groups can be used toscroll through information, which is available in form of a menu fordisplay but exceeds the amount of information, which can be displayedsimultaneously on display. Buttons can be used to select or enterinformation and to interact with the menu following a command andcontrol concept.

FIG. 69 illustrates the window content of a step in a series of user-bedinteraction processes that can be displayed on a detached device such asa general purpose computer. This is part of an interface which forexample can provide remote access to control, diagnose, or monitorfunctions of the bed system. The interface can provide functions toselect certain components from a list of components or subsystems of thebed system for detailed investigation. The user interface may change itslook and feel by changing some or all of its user interface componentswhen selecting to investigate a specific component of the bed system.The user interface can provide and display information in a categorizedgraphical fashion and can utilize a button status field, a motor statusfield, fields for monitoring vital information about a supported personetc. The user interface can also provide a menu system to select fromproviding access to different aspects of interaction of the bed systemsuch as for example, a monitoring interface, a maintenance interface, anoperator interface etc. Switching between these modes may requireauthorization and may be password or security code protected.

FIG. 70 illustrates an embodiment of a part of the user interfaceintended for use by the supported person. As illustrated, the userinterface for the supported person can provide access to recliningfunctions, emergency call functions or control of entertainmentequipment.

As noted previously FIG. 8A, illustrates a schematic diagram of thesystem architecture of a bed control and diagnostic system. Thearchitecture can be divided into a number of user interface and controlsubsystem components. The system architecture comprises a power or ACcontrol system for supplying electrical power, an actuator subsystemproviding ability for positioning and orienting parts of the bed, anumber of sensor and detector subsystems for sensing and detecting thestate of parts of the bed, and a diagnostic subsystem as indicated. Thediagnostic subsystem can interact with the sensor and detector subsystemor it can have its own redundant sensor and detector system. The userinterface subsystem can comprise a number of control consoles andcomprising indication or display systems. The display systems can have atouch screen or a regular display with separate buttons. The sensorsystem can comprise a scale subsystem including a load cell system andtilt sensor. The system architecture can further comprise a room orother interface for communicating information from the bed to a remoteuser interface system or vice versa.

FIG. 62 illustrates the information made available by a load cellsystem, which is used for monitoring movement of a patient. The systemcan be integrated into the patient support or can be part of a personsupport element such as a lying surface. In addition, the load cellsystem can comprise a number of load cells or load sensors for example aload cell which can be embedded in the bed proximally positioned at eachof a supported person's limbs and optionally at the center of the bed.The load cell system also can be comprised of a mesh of load cells forexample. The signals from the load cells can be monitored and processedby a processing unit in the load cell system or a central processingunit capable of monitoring, processing, and controlling signals from thebed's subsystems. Instead of forming part of a support element, the loadcell system can be integrated into the surface of the bed frame. Theload cell system can provide a measure for the pressure, weight, or massload of a certain load cell, for example foot left or right load cellvalues and head left or right load cell values and additionalinformation about the location of the center of gravity.

FIG. 71 schematically illustrates an embodiment of the motor controlsubsystem with a number of attached actuators and limit switches. It isunderstood that, depending on the functionality of the bed, there can bea different number of actuators or limit switches than illustrated. Inthis embodiment the surface of the bed can be shaped by orienting ahead, thigh, and a foot section where the bed surface for a supportedperson is intended to fold and provide an adjustable angle between theupper body and the thigh as well as under the knee between the thigh andthe lower leg. The head actuator can position the end of the headsection, and the thigh actuator can position the knee section of the bedsurface relative to an even or flat support structure. The HI-LO headactuator can position the head-end of the even support structurerelative to the frame of the bed which is in contact with the floor. TheHI-LO foot actuator can position the foot-end of the even supportstructure relative to the frame of the bed, for example. The two HI-LOactuators can pivot the support surface horizontally whereas the headand the thigh actuator can shape the support surface by pivotallyadjusting sections of the bed surface.

The motor control subsystem is connected to a number of limit switch orangle sensor systems which ensures that the actuators do not move orposition parts beyond predetermined limit angles or distances. When apart or section of the bed reaches a predetermined limit position whilemoving, the motor control subsystem can receive a status change signalvia one or more limit sensor signals and can interrupt the respectivemovement. The motor control subsystem can have a safety control featurethat does not allow any further continued movement in that samedirection or orientation unless the limit condition indicated by thelimit sensor system is resolved. Provided that no movement of otherdegrees of freedom of the bed takes place, the limit condition typicallycan be resolved by reversing the original movement.

FIG. 72 schematically illustrates an embodiment of the user interfacecontroller with a number of attached user interface consoles. The bedcan have a number of user-interface consoles, each providing access to acertain set of bed system functions. For example the bed can have userinterface consoles integrated into one or both of the side rails of thebed providing easy access to certain bed system functions for asupported person or for a person at the side of the bed. The bed canalso have a user interface console located at the foot or the headsection of the bed. Each such interface console may be integrated into arespective foot or head board of the bed for example. A foot or a headinterface console may provide access to a set of bed system functionsdifferent from each other as well as different from the side railconsoles. There can be inner or outer side rail consoles intended foraccess from within or from outside of the bed. An embodiment of a siderail console is illustrated in FIG. 70 and an embodiment of a footboardinterface console is illustrated in FIG. 68. The footboard console canhave a display system included. The display system can be a touch screendisplay or a simple passive display system with a separate input systemas illustrated in FIG. 68. In addition the interface controller can havea remote control interface to which a remote console can be connected.The remote control interface can provide wired or wireless connection ofa special purpose or a general purpose computing device for example. Anumber of different bus systems and control protocols are available tocommunicate through the remote control interface as known to a personskilled in the art. The interface controller may also provide a numberof additional control or remote control interfaces.

FIG. 73 illustrates a part of a scale subsystem. The scale subsystem canconnect to a number of load sensors or load cells. The number of loadsensors can be different from that illustrated. In this embodiment, fourload sensors which are capable of sensing pressure and can be calibratedto provide a measure of force or mass applied to each sensor areattached to the scale subsystem control interface. The scale subsystemcontroller can process signals incoming from the load cells and can beused to detect the status of a supported person. The scale controlsubsystem can be configured to provide a messaging signal or to alertmonitoring personnel through an external alarm system interface forexample. When each load cell is properly calibrated, the scale controlsubsystem can also provide a measure of the weight of a supportedperson, which is then compensated by the angle of the bed to provide theactual weight. The weight information can be utilized and can also berecorded in another subsystem of the bed which may be desired forpatient monitoring for example. As previously described, the angle ofthe bed and the load sensor measurements are used to calculate thepatient's actual weight, independent of the bed's position.

FIG. 74 illustrates an embodiment of a power supply system. The powersupply system may include an adaptation subsystem including atransformer and an adaptive wiring and plugging subsystem to achievecompatibility with standard power outlets and the different voltagestandards of other regions or countries.

FIG. 75 schematically illustrates the communication interface of the CANboard controller for communication with other components of the bed. Thecommunications interface includes sub-interfaces for side rail consoles,footboard consoles, remote monitoring consoles, external alarm system,speakers, an entertainment system etc.

Actuator Speed Compensation Circuit

Referring to FIG. 76, the bed of the present invention optionallyincorporates an actuator speed compensation circuit 1170. Circuit 1170includes at least one angle sensor 1171 located at any convenientlocation on the upper frame of the bed, for example, to the deck frame,to provide an actual angle of inclination indication relative tohorizontal. An angle store 1172 is provided to store the angle valuebefore a change in elevation is initiated. The respective outputs 1173and 1174 from the actual angle sensor 1171 and the angle store 1172 areconnected to a common node 1176 which forms the input 1177 to an angleprocessor 1178.

The processor 1178 contains and processes an algorithm that monitors theangle of the upper frame and, when necessary, adjusts the relative speedof rotation of either one or both of the actuators 504, also known asHi-Lo actuators or motors, so as to maintain the appropriate angle forthe upper frame. For example, and in this particular embodiment, theangle sensor 1171 produces a linearly varying first signal which iscompared to a stored second signal representative of the angle inexistence prior to the initiation of a height change. The sum of the twosignals at the node 1176 will produce an input signal at 1177 to theprocessor 1178 which will then process the input signal to produce, inaccordance with the algorithm, at least a first actuator speed controlsignal at 1179 for one of the actuators 504 and, depending on the setupof the bed and algorithm used, a second motor speed control signal forthe other motor actuator 504. The first and second motor speed controlsignals are fed through respective outputs 1181, 1182 from the processor1178 through respective power amplifiers 1183, 1184 to the respectiveactuators 504 in order to effect a driving force of the actuators at theproper speed to maintain unchanged the angle, in existence prior tobeginning the elevation change, throughout the change in elevation ofthe upper frame relative to the base frame.

According to one embodiment of the present invention, actuators 504 havethe linear speed and are configured to initially operate at maximumcapacity during initiation of a height adjustment (either raising orlowering) of the upper frame. Absent any load upon the upper frame, bothactuators 504 will continue to operate at maximum capacity and willexhibit substantially equal speeds, resulting in both ends (head-end andfoot-end) of the upper frame raising or lowering at the same speed,thereby maintaining the angle of the upper frame.

Typically, however, the upper frame will be supporting a load, such as,for example, a person sitting or lying upon the patient support deck.Furthermore, this load is frequently distributed unevenly across theframe such that a first end of the frame will be subject to a greaterload than the opposite, second end of the frame. In this situation,initiation of a height change in the upper frame results in bothactuators 504 initially operating at their maximum capacity. However,due to the unevenly distributed load, the actuator at the first end ofthe frame functions at a decreased speed. As a result of this decreasedspeed, the first end of the frame raises or lowers at a slower rate thanthe opposite, second end of the frame, resulting in a change in theangle of the upper frame.

Processor 1178 detects the change in the angle of the upper frame bymeans of the angle sensor 1171. The speed of the actuator at the secondend of frame is subsequently adjusted so as to substantially match thelower speed of the actuator at the first end of the frame. In thismanner, the speeds of the two actuators remain substantially matchedduring adjustments in the height of the upper frame, thereby allowingthe angle of the frame to be maintained.

To illustrate the above process, consider the following example where a200 lb person sits on the head-end of the patient support deck. Thehead-end actuator operates at its maximum capacity upon initiation of aheight change in the frame, yet due to the 200 lb load at the head-endof the patient support deck, the speed of the head-end actuatordecreases by 20% compared to when no load is present. Processor 1178detects the initial changes in the angle of the upper frame and reducesthe speed of the foot-end actuator by 20% so as to assure that both endsof the upper frame raise or lower at the same rate. The head-endactuator returns to its maximum, unloaded rate upon removal of the 200lb load from the head-end of the patient support deck. This increase inspeed in the head-end actuator is detected as initial deviations in theangle of the upper frame, upon which the speed of the foot-end actuatoris increased to match the speed of the head-end actuator.

To carry out the above example, processor 1178 is programmed with one ormore specific algorithms for monitoring and adjusting the angle of theupper frame. One example of such an algorithm is illustrated in the flowchart of FIG. 77. According to this illustrated algorithm of FIG. 77,the first step 1200 involves the motor speed compensation circuit 1170receiving and initiating the appropriate procedure for changing theheight of the upper frame. At this step 1200, the current angle of theupper frame is determined by means of the angle sensor 1171 and storedin the angle store 1172. Both Hi-Lo actuators 504 are then activated instep 1200. At step 1230, the angle sensor 1171 is then checked again todetermine the current angle of the upper frame. A comparison of thecurrent angle to the starting angle retained in the angle store 1172 isthen carried out at step 1240. If the two angles are found to be equal,the algorithm proceeds on to step 1250 to determine if the upper framehas reached the desired height. If it is determined that the desiredheight has been achieved, both actuators 504 are stopped, otherwise thealgorithm loops back to step 1230 and repeats. If it is determined atstep 1240 that the current angle is beginning to vary from the startingangle, the algorithm proceeds on to step 1242 and, for example,decreases the speed of the second motor actuator 504, thereby causingboth ends of the upper frame to raise or lower at the same rate, therebymaintaining the angle of the frame.

According to an alternative embodiment of the present invention,corrections to the angle during the raising or lowering of the upperframe are achieved through adjustment of the speed of the actuatorsupporting the greatest load. Specifically, instead of decreasing thespeed of the motor subject to less load, the current embodimentincreases the speed of the motor supporting the greatest load. In thismanner, the decreased speed caused by an increased load is directlyaddressed by increasing the power output of the actuator. However,unlike the previously described approach, the current embodimentrequires that the actuators be configured to run at less than maximumcapacity when in an unloaded state.

According to yet another alternative embodiment of the presentinvention, corrections to the angle during the raising or lowering ofthe upper frame are achieved through adjustment of the speeds of bothactuators 504. To accomplish such a task, an algorithm such as the oneillustrated in the flow chart of FIG. 78 is carried out by the processor1178. Steps 1300-1340 and 1350-1360 are similar to the primary steps1200-1240 and 1250-1260 required in the algorithm of FIG. 77, and assuch, will not be discussed. However, according to the illustratedalgorithm of FIG. 78, upon determining that the starting angle isgreater than the current angle, the speed of one of the actuators isdecreased while the speed of the opposite actuators is increased. Forexample, as illustrated in the flow chart of FIG. 78, step 1346 mayrequire that the actuator located at the head-end of the bed unit bedecreased by amount X, while the actuator located at the foot-end of thebed unit is increased by an amount Y, where X and Y represent either aspecific amount of speed, or, alternatively, a percentage of the currentspeed of the head-end and foot-end actuators, respectively. Similarly,if the current angle is found to be less than the starting angle, step1348 can require that the speed of the actuator located at the head-endof the bed unit be increased by an amount X, while the speed of theactuator located at the foot-end of the bed unit be decreased by anamount Y. It should be understood that the above actions may need to bereversed depending on where the angle sensor 1171 is located and how itis interpreted. For example, step 1346 may instead require that theactuator located at the head-end of the unit be increased by an amountX, while the speed of the actuator located at the foot-end of the unitbe decreased by an amount Y.

In addition to the algorithms discussed above with reference to FIGS. 77and 78, other equivalent actuator control schemes can, if desired, beutilized. For example, instead of controlling actuator speed, one suchscheme may call for the selective activation of actuator, therebyturning one actuator on or off, prior or subsequent to the otheractuator, in order to correct for deviations in the angle of the upperframe.

It is understood that variations may be made to the above descriptionwithout departing from the spirit of the invention. The foregoingdescription is therefore not intended to limit the scope of theinvention in any way.

1. A patient bed comprising: a base; a patient support; and an elevationmechanism for raising or lowering said patient support relative to saidbase, said elevation mechanism comprising a first pair of arms and asecond pair of arms, said pairs of arms mounted relative to said patientsupport and said base, said first pair of arms and said second pair ofarms having pivot connections at said patient support, and said pivotconnections of at least one pair of said pair of arms moving in asinusoidal path when said patient support is raised or lowered withrespect to said base.
 2. The patient bed according to claim 1, furthercomprising at least one actuator for driving each pair of arms.
 3. Thepatient bed according to claim 2, wherein each of said arms has an upperarm portion and a lower arm portion, said upper arm portions beingpivotally mounted to said lower arm portions, said upper arm portionsbeing pivotally mounted at said patient support by said pivotconnections, said lower arm portions being pivotally mounted to saidbase, and said upper arm portions being biased upwardly relative to saidlower arm portions by a spring force.
 4. The patient bed according toclaim 3, wherein said biasing forces reduces the load on the actuators.5. The patient bed according to claim 2, wherein said actuatorsselectively actuate to pivot said lower arm portions relative to saidbase, said lower arm portions being linked to said upper arm portions bylinkages, and said linkages configured to pivot said upper arm portionsrelative to said lower arm portions when said lower arm portions pivotabout said base.
 6. The patient bed according to claim 1, said basehaving a longitudinal axis, wherein said patient support is locatedbetween two vertical generally parallel planes spaced along saidlongitudinal axis when said patient support is lowered to said base, andwherein said elevation mechanism moves said patient support relative tosaid base and is configured to generally maintain said support framesystem between said two vertical planes when moving said support framesystem.
 7. The patient bed according to claim 6, wherein said elevationmechanism is configured to raise or lower said patient support relativeto said base with a longitudinal deviation relative to said longitudinalaxis of less than about 1 inch.
 8. The patient bed according to claim 7,wherein said deviation is less than about ½ inch.
 9. The patient bedaccording to claim 1, wherein said sinusoidal path has a maximumamplitude of less than about 1 inch.
 10. The patient bed according toclaim 9, wherein said maximum amplitude is less than about ½ inch.
 11. Apatient bed comprising: a base, said base having a longitudinal axis; apatient support mounted for movement relative to said base, said patientsupport having a head-end and a foot-end, said head-end of said patientsupport being aligned in a first vertical plane generally perpendicularto said longitudinal axis, and said foot-end being aligned in a secondvertical plane generally perpendicular to said longitudinal axis andspaced from said first vertical plane; an elevation mechanism forraising or lowering said patient support relative to said base and beingconfigured to (a) raise said foot-end relative to said head-end; and (b)raise said head-end relative to said foot-end; and said elevationmechanism being configured to move said patient support relative to saidbase in a manner to generally maintain said patient support between saidfirst vertical plane and said second vertical plane when moving saidpatient support relative to said base.
 12. The patient bed according toclaim 11, wherein said elevation mechanism is configured to raise orlower said patient support relative to said base with a maximumlongitudinal deviation along said longitudinal axis of less than about ½inch.
 13. The patient bed according to claim 11, wherein said elevationmechanism for raising or lowering said patient support relative to saidbase comprises a first pair of arms and a second pair of arms, saidpairs of arms mounted relative to said patient support and said base.14. The patient bed according to claim 13, further comprising at leastone actuator for driving each pair of arms.
 15. The patient bedaccording to claim 14, wherein each of said arms has an upper armportion and a lower arm portion, said upper arm portions pivotallymounted to said lower arm portions, said upper arm portions pivotallymounted at said patient support, and said lower arm portions beingpivotally mounted to said base.
 16. The patient bed according to claim15, wherein each of said upper arm portions is biased upwardly relativeto a respective lower arm portion by a spring force.
 17. The patient bedaccording to claim 16, further comprising a plurality of springs, saidsprings generating said biasing forces.
 18. The patient bed according toclaim 15, wherein said actuators are selectively actuated to pivot saidlower arm portions relative to said base, said lower arm portions beinglinked to said upper arm portions by linkages, and said linkagesconfigured to pivot said upper arm portions relative to said lower armportions when said lower arm portions pivot about said base.
 19. Thepatient bed according to claim 18, wherein said each of said lower armportions is connected to a respective upper arm portion by first andsecond linkages.
 20. The patient bed according to claim 19, wherein eachof said first linkages and said second linkages includes a longitudinalextent, said longitudinal extent of each of said first linkage beingnon-parallel with the longitudinal extent of its respective secondlinkage.
 21. The patient bed according to claim 20, wherein said lowerarm portions are pivotally mounted to said base about a first pivotaxis, said first and second linkages of each of said lower arm portionsbeing pivotally mounted to said base about a second pivot axis spacedfrom said first pivot axis, an opposed end of each of said first andsecond linkages being pivotally mounted to a respective upper armportion offset from said pivot axe of said respective upper arm portionrelative to its respective lower arm portion.
 22. The patient bedaccording to claim 21, wherein each of said arms includes a spring, suchas a torsion spring, for applying a biasing force to said upper armportions of said respective arm.
 23. The patient bed according to claim22, wherein each of said spring is configured to reduce the load on arespective actuator at least over a portion of the range of motion ofthe respective actuator.
 24. A patient bed comprising: a base; a patientsupport; and an elevation mechanism for raising and lowering saidsupport patient relative to said base, said elevation mechanismcomprising a first pair of arms and a second pair of arms, said firstpair of arms and said second pair of arms mounted relative to saidpatient support and said base, each of said arms having an upper armportion and a lower arm portion, said upper arm portions pivotallymounted to said lower arm portions and at said patient support, saidlower arm portions pivotally mounted at said base, each of said upperarm portions being biased upwardly relative to said lower arm portionsby a spring force, said elevation system further including an actuatorcooperating with each pair of said arms, said actuators selectivelyactuating to pivot the lower arm portions relative to said base, saidlower arm portions being linked to said upper arm portions by linkages,said linkages configured to pivot said upper arm portions relative tosaid lower arm portions when said lower arm portions pivot about saidbase.
 25. The patient bed according to claim 24, wherein said each ofsaid lower arm portions is connected to a respective upper arm portionby first and second linkages.
 26. The patient bed according to claim 25,wherein each of said first linkage and said second linkage includes alongitudinal extent, said longitudinal extent of each of said firstlinkage being non-parallel with the longitudinal extent of itsrespective second linkage.
 27. The patient bed according to claim 26,wherein each of said linkages has a first end and a second end, saidlower arm portions being pivotally mounted at said base about a firstpivot axis, said first and second linkages of each of said lower armportions being pivotally mounted at said base at their respective firstends about a second pivot axis spaced from said first pivot axis, saidsecond end of each of said first linkage and said second linkage beingpivotally mounted to a respective upper arm portion offset from saidpivot axe of said respective upper arm portion relative to itsrespective lower arm portion.
 28. The patient bed according to claim 27,wherein each of said arms includes a spring, such as a torsion spring,for applying said biasing force to said upper arm portions of saidrespective arm.
 29. The patient bed according to claim 28, wherein eachof said springs is configured to reduce the load on a respectiveactuator at least over a portion of the range of motion of therespective actuator.
 30. The patient bed according to claim 24, whereinsaid actuators comprise linear actuators.
 31. The patient bed accordingto claim 24, further comprises a control system controlling saidelevation mechanism.
 32. The patient bed according to claim 24, furthercomprising a detection system and a display, said detection system incommunication with said control system and being adapted to sense thestatus of said elevation system, and said detection system being incommunication with said display, and said display displaying the statusdetected by said detection system.